Sine Wave To TTL Converter

Sine Wave To TTL Converter is a series that we can use to change the sine wave signal with a pulse shape with the same frequency with TTL logic level that we are ready to use in coding the data digitally . The series of Sine Wave To TTL Converter can be used to convert sine wave signal to form a TTL of frequency 100KHz to 80MHz at the level of 100mV - 2V. The series of Sine Wave To TTL Converter uses a 5VDC voltage source. The series of Sine Wave To TTL Converter was built from transistor T1 gets base bias from R3, R4 and R5. If the series Sine Wave Converter This TTL To get the input sine signal with a minimum level of 100mV, the circuit Sine Wave To TTL Converter This will generate an output signal with TTL level square wave.

The series of Sine Wave To TTL Converter has input + impedance - 50 Ohm which is set using the R6. To change the value of the input impedance converter circuit Sine Wave To this TTL can be set via the R6 with a maximum value of 300 ohms.

Read more

Transistor As a timer circuit

Basically on all timer or timer circuit utilizing most of the basic characteristics of the capacitor.

 The basic characteristic is the process of filling and discharge that occurs in the capacitor. The length of time charging and release depends on the value of the capacitor.

If we observe the above circuit, the light will immediately switch SW1 turns on when we plug it into potensio VR1, this is because the current flowing from VR1 to trigger the transistor base should fill the first capacitor C1. Semakian large capacitance value of C1 then the longer the time required by the transistor to turn on the lights. Then if we connect it to the Ground SW1 then light would soon die and the capacitor will immediately clear the cargo. So can we draw the conclusion that the transistor can be used as a timer circuit using capacitor charging and discharging properties.

Read more

Audio Power Amplifier LM3886

Audio Power Amplifier is an important part in the reproduction of sound in a sound system. Audio Power Amplifier LM 3886 with power IC Audio Power Amplifier is a highly capable and able to produce 68 Watts with power rata2 4Ohm load and capable of producing power 38 Watt with 8Ohm load. With good sound reproduction capabilities of 20Hz-20kHz is also included on this LM3886 Audio Power Amplifier. LM3886 Audio Power Amplifier is equipped with spike protection that will protect the output circuit from overvoltage, undervoltage, overloads, konrsleting power supply, thermal runawaydan peak temperature. Audio Power Amplifier LM3886 also features a noise reduction system which can keep the audio from the noise well.

Image of Basic Audio Power Amplifier Series LM3886

Audio Power Amplifier LM3886

Feature owned LM3886 Audio Power Amplifier

• 68W cont. avg. output power into 4Ω at VCC = ± 28V
• 38W cont. avg. output power into 8Ω at VCC = ± 28V
• 50W cont. avg. output power into 8Ω at VCC = ± 35V
• 135W instantaneous peak output power capability
• Signal-to-Noise Ratio ≥ 92dB
• An input mute function
• Output protection from a short to ground or to the supplies via internal current limiting circuitry
• Output over-voltage protection against transients from inductive loads
• Supply under-voltage protection, not allowing internal biasing to occur Pls | VEE | + | VCC | ≤ 12V, Thus eliminating turn-on and turn-off transients
• 11-lead TO-220 package
• Wide supply range 20V - 94V
• Application of Audio Power Amplifier LM3886
• Stereo audio system
• Active Speaker
• High End Audio Power TV
• Suround Power Amplifier

Read more

1000 Watt Power Amplifier

Power amplifier has up to 1000 Watt power, this circuit made one channel only so if you want to create a stereo in it must be made one again, actually this is more suitable power amplifier in use for Sound System or outdoor, so if only in use for the house I think is less suitable.
Maybe youve seen or even have an active speaker and there is written 1500 watts PMPO (Peak Music Power Output), make no mistake this is different from Power Amplifier Active Speaker, I often dismantle such Active Speaker in it only a power with power no more than 150 watts by using the transformer 2-3 Ampere. PMPO is not a real power which is issued by the Power Amplifier, but counting all the speakers that there is, for example: if there are 5 pieces of speakers on each channel and each speaker has a power of 10 W then it is 100 W PMPO.

1000W Power Amplifier schematics

Part List 1000W amplifier

While this 1000 Watt Power Amplifier minimal use transformer 20 Ampere. And the output of Power Amplifier DC voltage contains approximately 63 volts, with currents and voltages of this magnitude, this 1000 Watt Power Amplifier will not hesitate hesitate to destroy your woofer speakers to connect. To overcome that then before the speaker on connects to 1000 Watt Power Amplifier must be in pairs Speaker Protector.

Actually if you want to create a Power Amplifier with great power does not have to make a Power Amplifier with great power. Example: you want to create a Power Amplifier with 10 000 Watt power. You do not have to assemble a Power Amplifier with power of 10,000 watts, but you assemble the power Power Amplifier Small but many, such as you assemble the Power Amplifier with 1000 Watts of power for as many as 10 pieces, it will produce 10 000 Watt Power Amplifier helpless.

Circuit uses power transistors pair of 5 x 5 x 2SA1216 and 2SC2922 and 2SC1583 use a differential amplifier that actually contains 2 pieces of transistors that are in containers together. Why use such built-in amplifier differental tujuanya so identical / similar, could have uses 2 separate transistors but can result in amplifier so it is not symmetrical.

Tips combining speaker.

To get the speakers with great power combining techniques can be used in parallel series, combining each group of speakers should sepaker they will have the same impedance, the same type (Woofer, Mid Range or tweeter) and the same power. Number of merging these speakers should consists of 4 , 9, 16 ff, see picture

Speaker wiring

Example: The number of speakers have 4 pieces each of its 200 Watt power generated will be a speaker at = 200 x 4 = 800 Watt. If there are 9 speakers 200 W then the result = 9 x 200 W = 1800 Watt.

Read more

Subwoofer power amplifier IC OPA541BM

Subwoofer power amplifier circuit based on IC OPA541BM very suitable for use in subwoofer speakers, these amplifiers possess excellence in sound issud because the sound is very clear and issued in accordance with subwoofer speakers in a low tone.

Subwoofer power amplifier IC OPA541BM Circuit

Read more

LM4651 and LM4652 170W power amplifier

170 Watt power amplifier is a power amplifier that is built by IC LM4651 and LM4652. Part of this power amplifier driver using the LM4651 IC designed specifically for the purpose of the class AB amplifier driver with short circuit protection feature, containing under voltage, thermal shutdown protection and standby functions. Section 170 Watt power amplifier using LM4651 IC with a MOSFET power amplifier is equipped with temperature sensors that will be used by IC LM4651 as controlnya thermal signal. IC IC LM4651 and LM4652 are designed specifically to each other in pairs to create a class AB power amplifier with protection features are detailed. Detailed series of 170 Watt power amplifier can be seen in thethe following figure .

Power amplifier circuit requires supply voltages +22 V DC symmetrical 0-22V. Power Amplifier with IC LM4651 and LM4652 are often used in portable HiFi systems such as powered speakers, power subwoofer and car audio power Booter. D1, D2, D3 and D4 in series 170 watt power amplifier with LM4651 and LM4652 is a 22V zener diode.

Read more

Vertical IC Configuration

Various kinds of vertical out IC configuration.Ac coupling -connect from the yoke deflection output to a coil connected directly.Dc coupling - connected the output to the coil through a capacitor deflectioan yoke. Electrolityc Capacitors (usually worth 1000u/35v). This configuration requires two kinds of voltage (the voltage mirror plus-minus).Dc input coupling using diffferential - uses 2 input from the driver IC.

Vertical IC Configuration AC Coupling

Vertical IC Configuration DC Coupling

Read more

PWM Motor Controller

PWM Motor Controller With Forward And Reverse is circuit controllers for DC motors controlled by PWM technique . The series PWM Motor Controller With Forward And Reverse It can control the DC motor rotation direction. Speed ​​control by PWM technique through MOSFETs Q1 IRF150. Then to play with the directional control relay which is controlled by Q10 using control signals in the form of logic 0 and 1. The series PWM Motor Controller With Forward And Reverse It requires 12 VDC supply voltage.

Circuit PWM Motor Controller With Forward And Reverse the above can be used to control large DC motor with maximum current consumption 10A.

Read more

METAL DETECTOR CIRCUIT

Metal detector is very common devices for checking the person in shopping malls, hotels, cinema halls to ensure that person is not carrying any explosive metals or illegal things like guns, bombs etc. metal detectors can be created easily and the circuit is not that complex.

Block Diagram

The LC circuit is nothing but inductor and capacitor which is connecter in parallel. The LC circuit will trigger the proximity sensor if it detects any metal near to it. Proximity sensor will give glow the led, and also make the buzz with the help of the buzzer.

Main Components in Metal Detector Circuit

LC CIRCUIT : LC Circuit is a resonating circuit which will resonate when exact same frequency material comes near. The LC circuit consist of inductor and capacitor connected in parallel , when the capacitor is fully charged the charge of the capacitor will be given to the inductor, here inductor will have improve its magnetic field. After some time the capacitor will have no charge and current from the inductor will be given to the capacitor in a reverse polarity and capacitor will get charge and now the inductor magnetic field and current will become nil. Again charged capacitor will give current to the inductor to improve its magnetic field. Note inductor is a magnetic field storage device and capacitor is electric field storage device.

PROXIMTY SENSOR : The proximity sensor can detect the objects with out any physical interference. The proximity sensor will work same as infrared sensor, proximity also release a signal, it will not give output unless and until there is no change in the reflected back signal, If there is a change in signal it will detect and give the output accordingly. There are different proximity sensors for example to detect plastic material we can use capacitive type proximity and for metals we should use inductive type.

Circuit Diagram

Circuit Working

• When the LC circuit that is L1 and C1 has got any resonating frequency from any metal which is near to it, electric field will be created which will lead to induces current in the coil and changes in the signal flow through the coil.
• Variable resistor is used to change the proximity sensor value equal to the LC circuit, it is better to check the value when there is coil not near to the metal. When the metal is detected the LC circuit will have changed signal. The changed signal is given to the proximity detector (TDA 0161), which will detect the change in the signal and react accordingly. The output of the proximity sensor will be of 1mA when there is no metal detected and it will be around 10mA when coil is near to the metal
• When the output pin is high the resistor R3 will provide positive voltage to transistor Q1. Q1 will be turned on and led will glow and buzzer will give the buzz. Resistor r2 is used to limit the current flow.

Read more

Digital to Analog Converter using Binary Weighted Resistors R 2R

The R-2R ladder DAC which is a binary-weighted DAC that uses a repeating cascaded structure of resistor values R and 2R. This improves the precision due to the relative ease of producing equal valued-matched resistors (or current sources). However, wide converters perform slowly due to increasingly large RC-constants for each added R-2R link. The D/A converter using binary-weighted resistors is shown in the figure below. In the circuit, the op-amp is connected in the inverting mode. The op-amp can also be connected in the non-inverting mode. The circuit diagram represents a 4-digit converter. Thus, the number of binary inputs is four.

Circuit Diagram

Fig. 1

We know that, a 4-bit converter will have 2⁴ = 16 combinations of output. Thus, a corresponding 16 outputs of analog will also be present for the binary inputs.

Four switches from b0 to b3 are available to simulate the binary inputs: in practice, a 4-bit binary counter such as a 7493 can also be used.

Working

The circuit is basically working as a current to voltage converter.

1. b0 is closed
It will be connected directly  to the +5V.
Thus, voltage across R = 5V
Current through R = 5V/10kohm = 0.5mA
Current through feedback resistor, Rf = 0.5mA (Since, Input bias current, IB is negligible)
Thus, output voltage = -(1kohm)*(0.5mA) = -0.5V

2. b1 is closed, b0 is open
R/2 will be connected to the positive supply of the +5V.
Current through R will become twice the value of current (1mA) to flow through Rf.
Thus, output voltage also doubles.

3. b0 and b1 are closed
Current through Rf = 1.5mA
Output voltage = -(1kohm)*(1.5mA) = -1.5V

Thus, according to the position (ON/OFF) of the switches (bo-b3), the corresponding “binary-weighted” currents will be obtained in the input resistor. The current through Rf will be the sum of these currents. This overall current is then converted to its proportional output voltage. Naturally, the output will be maximum if the switches (b0-b3) are closed,

V0 = -Rf *([b0/R][b1/(R/2)][b2/(R/4)][b3/(R/8)]) 

Where each of the inputs b3, b2, b1, and b0 may either be HIGH (+5V) or LOW (0V).

The graph with the analog outputs versus possible combinations of inputs is shown below.

Fig. 2

The output is a negative going staircase waveform with 15 steps of -).5V each. In practice, due to the variations in the logic HIGH voltage levels, all the steps will not have the same size. The value of the feedback resistor Rf changes the size of the steps. Thus, a desired size for a step can be obtained by connecting the appropriate feedback resistor. The only condition to look out for is that the maximum output voltage should not exceed the saturation levels of the op-amp. Metal-film resistors are more preferred for obtaining accurate outputs.

Disadvantages

If the number of inputs (>4) or combinations (>16) is more, the binary-weighted resistors may not be readily available. This is why; R and 2R method is more preferred as it requires only two sets of precision resistance values.

Read more

LM390 Simple 2 Way intercom Circuit

This is a very simple two way intercom circuit based on a LM390 audio amplifier circuit . the intercom circuit is a stand-alone electronic communications system intended for limited or private dialogue. For this circuit you can use a 8 ohms speaker, one for each station and require a 6 volts dc power supply. Gain control can be done by capacitively coupling a resistor (or FET) from pin 6 to ground.

LM390 Simple 2-Way intercom Circuit

LM390 Pin out

The LM390 Power Audio Amplifier is optimized for 6V, 7.5V, 9V operation into low impedance loads. The gain is internally set at 20 to keep the external part count low, but the addition of an external resistor and capacitor between pins 2 and 6 wil increase the gain to any value up to 200. The inputs are ground referenced while the output is automatically biased to one half the supply voltage.

Read more

Transistor Schmitt Trigger Oscillator

The Schmitt Trigger oscillator below employs 3 transistors, 6 resistors and a capacitor to generate a square waveform. Pulse waveforms can be generated with an additional diode and resistor (R6). Q1 and Q2 are connected with a common emitter resistor (R1) so that the conduction of one transistor causes the other to turn off. Q3 is controlled by Q2 and provides the squarewave output from the collector.

In operation, the timing capacitor charges and discharges through the feedback resistor (Rf) toward the output voltage. When the capacitor voltage rises above the base voltage at Q2, Q1 begins to conduct, causing Q2 and Q3 to turn off, and the output voltage to fall to 0. This in turn produces a lower voltage at the base of Q2 and causes the capacitor to begin discharging toward 0. When the capacitor voltages falls below the base voltage at Q2, Q1 will turn off causing Q2 and Q3 to turn on and the output to rise to near the supply voltage and the capacitor to begin charging and repeating the cycle. The switching levels are established by R2,R4 and R5. When the output is high, the voltage at the base of Q2 is determined by R4 in parallel with R5 and the combination in series with R2. When the output is low, the base voltage is set by R4 in parallel with R2 and the combination in series with R5. This assumes R3 is a small value compared to R2. The switching levels will be about 1/3 and 2/3 of the supply voltage if the three resistors are equal (R2,R4,R5).

There are many different combinations of resistor values that can be used. R3 should low enough to pull the output signal down as far as needed when the circuit is connected to a load. So if the load draws 1mA and the low voltage needed is 0.5 volts, R3 would be 0.5/.001 = 500 ohms (510 standard). When the output is high, Q3 will supply current to the load and also current through R3. If 10 mA is needed for the load and the supply voltage is 12, the transistor current will be 24 mA for R3 plus 10 mA to the load = 34 mA total. Assuming a minimum transistor gain of 20, the collector current for Q2 and base current for Q3 will be 34/20 = 1.7 mA. If the switching levels are 1/3 and 2/3 of the supply (12 volts) then the high level emitter voltage for Q1 and Q2 will be about 7 volts, so the emitter resistor (R1) will be 7/0.0017 = 3.9K standard. A lower value (1 or 2K) would also work and provide a little more base drive to Q3 than needed. The remaining resistors R2, R4, R5 can be about 10 times the value of R1, or something around 39K.

The combination of the capacitor and the feedback resistor (Rf) determines the frequency. If the switching levels are 1/3 and 2/3 of the supply, the half cycle time interval will be about 0.693*Rf*C which is similar to the 555 timer formula. The unit I assembled uses a 56K and 0.1 uF cap for a positive time interval of about 3.5 mS. An additional 22K resistor and diode were used in parallel with the 56K to reduce the negative time interval to about 1 mS.

In the diagram, T1 represents the time at which the capacitor voltage has fallen to the lower trigger potential (4 volts at the base of Q2) and caused Q1 to switch off and Q2 and Q3 to switch on. T2 represents the next event when the capacitor voltage has risen to 8 volts causing Q2 an Q3 to turn off and Q1 to conduct. T3 represents the same condition as T1 where the cycle begins to repeat. Now, if you look close on a scope, you will notice the duty cycle is not exactly 50% This is due to the small base current of Q1 which is supplied by the capacitor. As the capacitor charges, the E/B of Q1 is reverse biased and the base does not draw any current from the capacitor so the charge time is slightly longer than the discharge. This problem can be compensated for with an additional diode and resistor as shown (R6) with the diode turned around the other way. 

Read more

Simple 2 1 Surround Speaker System Circuit Diagram

 "Simple 2.1 Surround Speaker System " . Here I have used  three TDA 2030 IC for making signal amplification . Here you need a sub filter extra ( Sub filter circuit diagram link showing below ) . This project  mostly used in computer  . Part list and applications are showing below.

Part List

Component No:	Value	Usage
All C1	100MF	Grounding
All C2	100nF	Grounding
All C3	100nF	Grounding
All C4	100MF	Grounding
All C5	100MF	Feedback
All C6	100MF	Audio Coupling
All C7	220nF	Noise Grounding
All R1	1K
All R2	10K ( Not 1K )
All R3	22K
All R4	22K (Not 1K )
All RV1	100K	Volume Controlling
All D1 To D2	IN4007	Potential Breaking
U1 To U6	TDA2030	Amplification

Applications* 2.1 Surround Amplifier

* 2.1 Home Theater

Read more

Wireless Microphone simple

 

  Wireless Microphone simple Parts list:

* T1,T2,T3: 2N2222 transistor
* R1: 10k 5%
* R2: 33k lin.
* R3: 12k 5%
* R4: 5.6k 5%
* R5: 2.2k 5%
* R6,R8: 47k 5%
* R7: 470 ohms 5%
* R9: 180 ohms 5%
* C1,C2: 47nF
* C3: 1nF
* C4: 33pF
* C5: 5.6pF
* C6: 8.2pF
* C7: 10nf
* L1: 3mm in diameter with 5 turns 0.61 mm copper wire
* K1: SPDT toggle switch
* Other parts: 2 AA battery holder, Electret microphone, antenna wire

Wireless FM microphone is simple to body and it has a advantageous transmitting ambit (over 300 meters in the accessible air). Despite its baby basic calculation and a 3V operating voltage it will calmly access over three floors of an accommodation building. It may be acquainted anywhere in the FM bandage (87-108MHz) and its transmissions can be best up on any accepted FM receiver.

The braid (L1) should be about 3mm in bore with 5 turns 0.61 mm chestnut wire. You can alter the Tx abundance by artlessly adjusting the agreement of the coils. The antenna should be a bisected or division amicableness continued (for 100 MHz 150 cm or 75 cm).

Circuit description:The audio addition date (T1) is a accepted accepted emitter amplifier. The 47nF capacitor isolates the microphone from the abject voltage of the transistor and alone allows AC signals to pass.

The LC catchbasin ambit is complete with T2, the acknowledgment capacitor C5 and the alongside LC ambit L1, C4. The coupling capacitor(C6) directs the arresting to the RF amplifier (T3).

Circuit calibration: Place the transmitter about 10 anxiety from a FM radio. Set the radio to about about 89 – 90 MHz. Spread the ambagious of the L1 braid afar to tune to the adapted frequency.

Read more

Webster TP45 17dBW PA amplifier 2 6L6GC schematic

Webster TP45 17dBW PA amplifier 2 6L6GC schematic

Read more

Simple Heat Sensor Circuit Diagram

This simple heat sensor circuit could senses heat from various electronics device like computer, amplifier etc. and generate warning alarm. It could senses heat from environment also, but here I mention “electronics device” because it is being using mostly in electronic device to protect them from overheat.

Thermistor, 110 Ohms:

Fig-2: 110 Ohms Thermistor

As it is a heat sensor circuit, here a thermistor is used as a heat sensor. It is a thermal measurement device and has a variety of usages including temperature sensor/ heat sensor. The thermistor used in this circuit is a NTC (Negative Temperature Coefficient) type thermistor. When temperature increases, its resistance goes decrease. Therefore, NTC thermistor’s resistances are inverse of temperature.

Circuit Description:

You have seen, in this simple circuit diagram of heat sensor, a few number of components is used including a BC548 transistor, a 110 ohms thermistor etc.

• BC548: BC548 is a TO-92 type NPN transistor, as its alternative you can use 2N2222, BC238, BC548, BC168, BC183 etc. they all have almost same characteristic.
• 110 Ohms Thermistor: A 110 Ohms thermistor is used to detecting heat. I have told already about it.
• Buzzer: A buzzer is used with +9V and collector of transistor. When the temperature/ heat exceeds a certain level then it make an alarm.
• 4.7V Zener diode:  It is used to limit the emitter current of BC548.
• 9V Battery: A 9V battery is used as a single power source.
• R1, R2: A 3.3K 1/4w resistor is used as R1 and 100 ohms 1/4w as R2.
• Switch: Here in this circuit the switch used is a simple SPST switch. You can either use the switch or not, choice is yours. It is not mandatory.
  

Read more

Car Head Lights Turn Off

This circuit when setup in a car automatically turns off the head light after a preset time after the ignition switch is turned off.So you can walk out easily from the dark garage in the light of your car.

Circuit diagram :

Car Head Lights Turn Off  Circuit Diagram

When the ignition switched on first the voltage from battery is fed to the relay through diode D1.When the ignition switch is turned off it produces a negative going pulse at the pin 2 that triggers the timer. The output of the IC goes high for the time set by R1  .This makes the transistor Q1 to conduct to energize the relay to drive the headlight.After the set time the light goes off.With the value of components used you can make a setting from 10 S to 60 S.
Notes :

• Assemble the circuit on a good quality PCB or common board.
• Fit the potentiometer on somewhere on the dashboard so that  you can easily set the timing.
  

Read more

Cheap Pump Controller

This simple but effective circuit can be used to control water level in a container. The prototype is used to pump water out of a bucket that collects condensation from a home air-conditioning system. The design is based around a 555 timer (IC1). Although the timer in configured as a mono-stable, it lacks the usual timing capacitor from pin 6 to ground. Instead, a metal probe inserted in the water provides a current path to a second, grounded probe. When the water level in the container reaches a third ("high") probe, the trigger input (pin 3) is pulled low, switching the 555 output high and energizing the relay via transistor Q1.

 

Cheap Pump Controller Circuit Diagram

Once the water level drops below the "low" probe, the threshold input (pin 6) swings high, switching the output (pin 3) low and the relay and pump off. The two 100kΩ pull-up resistors can be replaced with larger values if more sensitivity is required (eg, if the 555 doesn’t trigger). A switch (S1) can be included to bypass the relay for manual emptying. The "low" probe should be positioned so that the pump doesn’t run dry.

The high level probe is placed at the level that you want the pump to start. Since the water is held at ground potential, you must use stainless steel or copper wire to slow corrosion. With water fountain pumps available for less than $10, this circuit offers a cheap alternative for those who have an air-conditioner on an internal wall and don’t want to be continually emptying the bucket on humid days.

Read more

Sound Activated Lights

This diy sound activated lights circuit turns a lamp ON for a short duration when the dog barks (or a relatively strong sound) giving an impression that the occupants have been alerted. The condenser microphone fitted in a place to monitor sound and generates AC signals, which pass through DC blocking capacitor C1 to the base of transistor BC549 (T1). Transistor T1 along with transistor T2 amplifies the sound signals and provides current pulses from the collector of T2. When sound is produced in front of the condenser mic, triac1 (BT136) fires, activates lights and the bulb (B1) glows for about two minutes.

Assemble the sound activated lights circuit on a general purpose PCB (circuit board) and enclose in a plastic cabinet. Power to the sound activated switch circuit can be derived from a 12V, 500mA step-down transformer with rectifier and smoothing capacitor. Solder the triac ensuring sufficient spacing between the pins to avoid short circuit. Fix the unit in the dog’s cage or close to the sound monitoring spot, with the lamp inside or outside as desired. Connect the microphone to the sount activated lights circuit using a short length of shielded wire. Enclose the microphone in a tube to increase its sensitivity.

Caution. Since the sound activated lights uses 230V AC, many of its points are at AC mains voltage. It could give you lethal shock if you are not careful. So if you don’t know much about working with line voltages, do not attempt to construct this circuit. We will not be responsible for any kind of resulting loss or damage.

Read more

Precision Headphone Amplifier

Designs for good-quality headphone amplifiers abound, but this one has a few special features that make it stand out from the crowd. We start with a reasonably conventional input stage in the form of a differential amplifier constructed from dual FET T2/T3. A particular point here is that in the drain of T3, where the amplified signal appears, we do not have a conventional current source or a simple resistor. T1 does indeed form a current source, but the signal is coupled out to the base of T5 not from the drain of T3 but from the source of T1. Notwithstanding the action of the current source this is a low impedance point for AC signals in the differential amplifier.  

Precision Headphone Amplifier Circuit Diagram

Measurements show that this trick by itself results in a reduction in harmonic distortion to considerably less than –80 dB (much less than 0.01 %) at 1 kHz. T5 is connected as an emitter follower and provides a low impedance drive to the gate of T6: the gate capacitance of HEXFETs is far from negligible. IC1, a volt-age regulator configured as a current sink, is in the load of T6. The quiescent current of 62 mA (determined by R11) is suitable for  an output power of 60 mWeff into an impedance of 32 Ω, a value typical of high-quality headphones, which provides plenty of volume.

Using higher-impedance headphones, say of 300 Ω, considerably more than 100 mW can be achieved. The gain is set to a useful 21 dB (a factor of 11) by the negative feedback circuit involving R10 and R8. It is not straightforward to change the gain because of the single-sided supply: this voltage divider also affects the operating point of the amplifier. The advantage is that excellent audio quality can be achieved even using a simple unregulated mains supply.  Given the relatively low power output the power supply is considerably overspecified. Noise and hum thus remain more than 90 dB below the signal (less than 0.003 %), and the supply can also power two amplifiers for stereo operation.

The bandwidth achievable with this design is from 5 Hz to 300 kHz into 300 Ω, with an output voltage of 10 Vpp. The damping factor is greater than 800 between 100 Hz and 10 kHz. A couple of further things to note: some-what better DC stability can be achieved by replacing D1 and D2 by low-current red LEDs (connected with the right polarity!). R12 prevents a click from the discharge of C6 when headphones are plugged in after power is applied. T6 and IC1 dissipate about 1.2 W of power each as heat, and so cooling is needed. For low impedance headphones the current through IC1 should be increased. To deliver 100 mW into 8 Ω, around 160 mA is required, and R11 will need to be 7.8 Ω (use two 15 Ω resistors in parallel).

To keep heat dissipation to a reasonable level, it is recommended to reduce the power supply volt-age to around 18 V (using a transformer with two 6 V secondaries). This also means an adjustment to the operating point of the amplifier: we will need about 9V between the positive end of C6 and ground. R4 should be changed to 100 Ω, and R8 to 680 Ω. The gain will now be approximately 6 (15 dB). The final dot on the ‘i’ is to increase C7 by connecting another 4700 µF electrolytic in parallel with it, since an 8 Ω load will draw higher currents.

Read more

Battery Equality Monitor

Almost all 24V power systems in trucks, 4WDs, RVs, boats, etc, employ two series-connected 12V lead-acid batteries. The charging system can only maintain the sum of the individual battery voltages. If one battery is failing, this circuit will light a LED. Hence impending battery problems can be forecast. The circuit works by detecting a voltage difference between the two series connected 12V batteries. Idle current is low enough to allow the unit to be permanently left across the batteries.

Battery Equality Monitor Circuit Diagram

Parts:

R1 = 2.K
R2 = 4.7K
R3 = 39K
R4 = 39K
R5 = 1.5K
R6 = 1.5K
Q1 = BC547
Q2 = BC547
Q3 = BC557
D1 = 3mm Red LED
D2 = 3mm GreenLED
B1 = DC 12 Volt
B2 = DC 12 Volt

Read more

Automotive Voltage Indicator

Monitors battery voltage, Three-LED Display. Connecting this circuit to the battery of your vehicle, you will always know at a glance the approximate voltage available. An indication of battery voltage is useful to the motorist for monitoring the batterys capacity to deliver current, and as a check on the efficiency of the dynamo or alternator. Threshold voltages of the Leds are set by means of two Zener Diodes (D6 & D10) plus two further Diodes wired in series (D4, D5 and D8, D9 respectively) adding a step of about 1.3V to the nominal Zener voltage.

Automotive Voltage Indicator Circuit Diagram :

Parts:
R1 = 1k
R2 = 100K
R3 = 1k
R4 = 3.3K
R5 = 3.3K
R6 = 1k
R7 = 3.3K
R8 = 3.3K
Q1 = BC547
Q2 = BC547
Q3 = BC557
D1 = Red Led
D2 = Amber Led
D3 = 1N4148
D4 = 1N4148
D5 = 1N4148
D6 = BZX79C10
D7 = Green Led
D8 = 1N4148
D9 = 1N4148
D10 = BZX79C12

Notes:

• Red LED D1 is on when battery voltage is 11.5V or less. This indicates a low battery charge.
• Amber LED D2 is on when battery voltage is comprised in the 11.5 - 13.5V range. This indicates that the battery is good if the motor is off. When motor is running, this indicates no charge from dynamo or alternator.
• Green LED D7 is on when battery voltage is 13.5V or more. This indicates a normal condition when motor is running and dynamo or alternator is charging.

Read more

Cable Tester

This cable tester allows you to quickly check audio cables for broken wires. Because of the low power supply voltage, batteries can be used which makes the circuit portable, and therefore can be used on location.

Cable Tester Circuit diagram:

The design is very simple and well organ-ised: using the rotary switch, you select which conductor in the cable to test. The corresponding LED will light up as indication of the selected conductor. This is also an indication that the power supply volt-age is present. If there is a break in the cable, or a loose connection, a second LED will light up, corresponding to the selected conductor. You can also see immediately if there is an internal short circuit when other than the corresponding LEDs light up as well.

You can also test adapter and splitter cables because of the presence of the different connectors.

Two standard AA- or AAA- batteries are sufficient for the power supply. It is recommended to use good, low-current type LEDs. It is also a good idea not to use the cheapest brand of connectors, otherwise there can be doubt as to the location of the fault. Is it the cable or the connector.

Read more

Regulated 24 Watt Broad Spectrum LED

This project involves constructing an energy efficient broad spectrum LED lamp system. The lamp is useful for indoor reflective room lighting. It has a broad color spectrum that more closely approximates the light of the sun when compared to fluorescent bulbs and white-only LEDs. The light level is regulated and the light that is produced does not flicker.

The six differently colored LED stars, made by LedEngin, Inc., are rated at 5 watts (nominal). The LED array and associated current regulator consume 1 amp at 24VDC (24 Watts). NEVER stare directly at this lamp when it is running at full operating power, it is DANGEROUSLY BRIGHT.

Regulated 24 Watt Broad Spectrum LED Circuit diagram : 

With the LEDs shown, the combined color of the lamp has a pinkish white hue. The 5 Watt ratings of the LEDs are not precise, the white, blue and green LEDs consume about 4W and the lower voltage red, orange and deep red LEDs consume about 3W. The current regulator keeps the LED brightness constant and insures that the LED series string never draws more than 1 amp of current.

The project has also been coined "Bold as LED" in reference to the Jimi Hendrix song "Bold as Love" which has the lyric: "My yellow in this case is not so mellow"

Specifications:

• Nominal operating power: 24 Watts (24V DC at 1 Amp)
• LED power consumption above regulation point: 18.6 Watts
• Maximum operating voltage: 28V DC
• Minimum voltage for regulated light: 23V DC
• Leds produce light down to 11V
• Deep Red LED voltage: 2.55V
• Red LED voltage: 2.37V
• Amber LED voltage: 2.60V
• Green LED voltage: 3.92V
• Blue LED voltage: 3.56V
• White LED voltage: 3.7V
• Voltage across regulator when current becomes regulated: 4.2V

Theory:

The lamp is wired as a current loop which includes the power supply, the LED series string and the 1 amp current regulator circuit. The LM317K and 1.2 ohm 5 Watt resistor act as a current regulator that limits the loop current to 1 Amp. During regulation, there will always be 1.2V across the 1.2 ohm resistor. The current regulator insures that the LEDs always run at their maximum brightness, but not so bright that they burn out. A 100uF electrolytic capacitor bypasses the DC power input to the device and a 100nF monoblock capacitor bypasses the LM317K input.

Construction:

The LEDs and current regulator circuit were mounted on a 3" x 8" chunk of 1/8" aluminum stock. The LM317K regulator and LED heat sinks were bolted to the chassis directly, heat sink grease was used on the regulator, the heat sinks and the six LEDs. Connecting the LM317K directly to the aluminum plate makes the plate electrically hot at 1.2V, the plate should not be allowed to come into contact with any live conductors. By using a few more parts, the LM317 can be mounted with an insulator and plastic shoulder washers for electrical isolation from the mounting plate.

The LEDs come mounted on their own small star-shaped aluminum substrates, these were attached to the aluminum plate using two 7/16" 4-40 screws and nuts per LED. A drop of silicone heat sink grease should be applied to the center of each LED star when it is mounted to the plate for heat conduction. It is important to use insulating plastic washers on the top side of the LED stars to prevent electrical contact with head of the screw. The LED stars were soldered together using short pieces of #20 tinned wire after being mounted on the plate. It is necessary to use a fair amount of heat to solder the contacts, a 200/240W soldering gun did the job. Be very careful not to melt the lenses on the LEDs, the LEDs cost around $10 each. The positive and negative leads of the LED series string were connected back to the current reglator circuitry using #20 wire covered with teflon insulation.

The initial mechanical arrangement did not pass the "rule of thumb" test, which says that if a semiconductor is too hot to hold your thumb on, it will not live a long life. Two large aluminum heat sinks were bolted to the back of the aluminum plate and seem to be sufficient to keep the lamp operating at a reasonable temperature. The LED array produces more heat than the LM317K.

Use:

Connect this circuit to a 24VDC power supply or other power source such as a solar-charged lead acid battery. Be sure to observe the correct polarity. Look away from the LEDs and apply power. Again, do not stare directly at the LEDs, they are bright enough to harm your vision. A switch-mode power supply rated at 24VDC and 1 Amp or more is probably the most energy-efficient way to power this device from line power.

Parts:

• 1x LM317K T03 case 1.5A adjustable voltage regulator
• 1x 1.2 ohm 5W resistor (or 2x 2.4 ohm 2W resistors in parallel)
• 1x 100uF 35V or higher electrolytic capacitor
• 1x 100nF 35V or higher monolythic capacitor
• 1x LedEngin LZ1-10R205 deep red 5W LED
• 1x LedEngin LZ1-10R105 red 5W LED
• 1x LedEngin LZ1-10A105 amber 5W LED
• 1x LedEngin LZ1-10G105 green 5W LED
• 1x LedEngin LZ1-10B105 blue 5W LED
• 1x LedEngin LZ1-10CW05 cool white 5W LED
• Miscellaneous wire, solder lugs, termination strips and hardware,
• Large aluminum mounting plate, heat sinks if necessary.

Read more

Simple Oscillator Pipe Locator

Sometimes the need arises to construct a really simple oscillator. This could hardly be simpler than the circuit shown here, which uses just three components, and offers five separate octaves, beginning around Middle C (Stage 14). Octave # 5 is missing, due to the famous (or infamous) missing Stage 11 of the 4060B IC. We might call this a Colpitts ‘L’ oscillator, without the ‘C’. Due to the reactance of the 100-µH inductor and the propagation delay of the internal oscillator, oscillation is set up around 5 MHz. When this is divided down, Stage 14 approaches the frequency of Middle C (Middle C = 261.626 Hz). Stages 13, 12, 10, and 9 provide higher octaves, with Stages 8 to 4 being in the region of ultrasound.

Simple Oscillator/Pipe Locator Circuit Diagram

If the oscillator’s output is taken to the aerial of a Medium Wave Radio, L1 may serve as the search coil of a Pipe Locator, with a range of about 50 mm. This is tuned by finding a suitable hetero-dyne (beat note) on the medium wave band. In that case, piezo sounder Bz1 is omitted. The Simple Oscillator / Pipe Locator draws around 7 mA from a 9-12 V DC source.

Read more

STK4132II Schematic audio amplifier power amplifier 2x20w

STK4132II - Schematic audio amplifier - power amplifier 2x20w

STK4132II  - Schematic audio amplifier.STK4132II  power audio amplifier schematic

Read more

TDA7294 150 W Power Amplifier

This is power amplifier based on IC TDA7294 with output power 150W with 8 ohm impedance, source voltage + - 25V. for circuit see image below.

TDA7294 Power Amplifier

Read more

AUDIO SCHEMATIC AND ROUTING ELECTRONIC DIAGRAM

AUDIO SCHEMATIC AND ROUTING ELECTRONIC DIAGRAM

It shows the connection and wiring between each parts and component of audio system of the vehicle such as the alternator, ignition switch, antenna meter, tail, audio, front speaker, rear speaker, tweeter speaker, and many more.

Read more

CAR AIR CONDITIONING ELECTRONIC DIAGRAM

CAR AIR CONDITIONING ELECTRONIC DIAGRAM

It shows the connection and wiring between each parts and component of Air Conditioning system of the vehicle such as the junction block, blower motor relay, blower resistor, blower switch, air conditioning switch, air conditioning control unit, air inlet sensor, air thermo sensor, engine control module, air conditioning engine coolant temperature switch, interior light system, dual pressure switch, heat control illumination light, interior lights system, air conditioning compressor magnetic clutch, condenser fan motor relay, relay box, and many more.

Read more