Petrol Gas Switch For A Pajero circuit and explanation

My current vehicle, a Pajero, was modified for dual fuel - ie, petrol and gas. However, its necessary to run the vehicle on petrol at regular intervals to stop the injectors from clogging up. This simple circuit allows the vehicle to be started using petrol and then automatically switches it to gas when the speed exceeds 45km/h and the brake pedal is pressed. Alternatively, the vehicle may be run on petrol simply by switching the existing petrol/gas switch to petrol. You can also start the vehicle on gas by pressing the brake pedal while starting the vehicle. The circuit is based on an LM324 dual op amp, with both op amps wired as comparators. It works like this: IC1a buffers the signal from the vehicles speed sensor and drives an output filter network (D1, a 560kO resistor and a 10µF capacitor) to produce a DC voltage thats proportional to the vehicles speed.

Circuit diagram:

This voltage is then applied to pin 5 of IC1b and compared with the voltage set by trimpot VR1. When pin 7 of IC1b goes high, transistor Q1 turns on. This also turns on transistor Q2 when the brake pedal is pressed (pressing the brake pedal applies +12V from the brake light circuit to Q2s emitter). And when Q2 turns on, relay 1 turns on and its contacts switch to the gas position. Trimpot VR1 must be adjusted so that IC1bs pin 7 output switches high when the desired trigger speed is reached (ie, 45km/h). In effect, the speed signal is ANDed with the brake light signal to turn on the relay. The vehicle has been running this circuit for several years now and is still running well, with no further injector cleans required.

Author: J. Malnar - Copyright: Silicon Chip Electronics

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Switch Mode Pre Regulator circuit diagram

Switch Mode Pre-Regulator Circuit

The botheration was that a voltage regulator had to bead the 18 volt capital ability accumulation voltage to 8 volts at 500ma to ability the CD player, crumbling 5 watts of ability and causing a lot of calefaction central the bunched unit. This ambit acts as an interference-free pre-regulator to abundantly abate the ability loss..

The achievement voltage of this ambit is artless by ability band fluctuations. Amount voltage aberration is alone abased on the on-resistance of Q2 and the amount of C2 (re: ripple). The achievement voltage can be set so that the ripple lulls are aloof aloft the drop-out voltage of the beeline regulator at best amount for best activity conservation. The college amount you aces for C2, the added activity you can save and the added abiding the pre-regulator’s achievement voltage.

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Build a Flashing Light with Twilight Switch Circuit Diagram

Build a Flashing Light with Twilight Switch Circuit Diagram. Flashing light is very useful in order to indicate any obstruction or working in progress. The project automatic flashing light with twilight switch flash light in dark but during day it automatically turns off itself.

The circuit diagram of automatic flashing light with twilight switch is shown below where LDR is used as sensor. In the presence of light LDR offer low resistance and in dark it offers high resistance. When there is absence light, LDR offer high resistances which turn off the transistor T1. Due to this darlington pair made from transistor T2 and T3 is turn on which further glow bulb. The feedback from its output is given to the junction of resistor R2 and LDR as shown in circuit diagram. Due to feedback this circuit works as oscillator which work as flasher. Variable resistor VR1 is used to adjust the sensitivity of LDR.

Flashing Light with Twilight Switch Circuit Diagram

 

 

PARTS LIST
Resistors (all ¼-watt, ± 5% Carbon unless stated otherwise)
R1 = 2.2 KΩ
R2, R3 = 1 KΩ
R4 = 3.3 KΩ
VR1 = 25 KΩ
Capacitors
C1 = 1 µF – 10 µF
Semiconductors
T1, T2 = BC547B
T3 = BEL187-P
Miscellaneous
LDR
B1 = 3V to 10V bulb

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TL594 12V DC Switch Mode Power Supply Circuit Diagram

Basic Of Switch Mode Power Supply

In recent years, the use of switch mode power supply (SMPS) has become more comon as more applications demand for greater power eficiency. It makes use of semiconductor (mostly MOSFET) fast switches to switch DC input that has been rectified at high frequency. The advantages of high frequency switching are that it reduces the size of inductor, capacitors & transformer used. Other advantages of switching power supply over linear power supply are :

1) High Efficiency (up to 90% and above for nice design).

2) Output can be higher than input.
3) Able to operate over a variety of input power supply.
4) Able to have over output.

The setback of using SMPS compared to linear power supply is that it generates electrical noise which contributes to electromagnetic compatibility design issues & more part count.

Buck Converter SMPS

The SMPS circuit below from Power Integration makes use of LNK304 as its high frequency switch. Take note that this circuit is non isolated type which means that the output is not electrically isolated from the input & all testing ought to be completed using an isolation transformer to provide the AC line input to the board.

Make positive that you have electrical safety knowledge & experience before you embark on doing this project.

12V DC Switch Mode Power Supply Circuit Diagram

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Simple B C with Automatic Switch off Circuit Diagram

This is a Simple Battery Charger with Automatic Switch-off Circuit Diagram. This lovely charger automatically switches off when your rechargeable batteries reach the full charge.The circuit comprises a bistable multivibrator wired around timer IC 555. The bistable output is fed to an ammeter (via diode D1) and pot meter VR1 before it goes to three Ni-Cd batteries that are to be charged.

Battery Charger with Automatic Switch-off Circuit Diagram

Normally, the full charge potential of an Ni-Cd cell is 1.2V. Trigger the bistable by pressing switch S1 and adjust potmeter VR1 for 60mA current through the ammeter.

Now remove the ammeter and connect a jumper wire between its points ‘a’ and ‘b.’ Connect the positive output terminal of the batteries to the emitter of pnp transistor T1. The base of transistor T1 is held at 2.9V by adjusting potmeter VR2. The output of transistor T1 is inverted twice by npn transistors T2 and T3.

Thus when the batteries are fully charged to 3×1.2V=3.6V, a voltage higher than this makes transistor T1 to conduct. Transistor T2 also conducts and transistor T3 goes off. The threshold level of timer 555 reaches 6V, which is more than 2/3×VCC = 2/ 3×6=4V, to turn off the timer.

During charging, the threshold level of the timer is held low. The green LED (LED1) glows during charging of the batteries and goes off at the attainment of full charge.

Note that this circuit can be used only for 1.2V, 600mAH Ni-Cd rechargeable batteries that require 60 mA of current for 15 hours to charge fully.

Author : V. Gopalakrishnan

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Audio Controlled Mains Switch Circuit Diagram

This is a simple Audio Controlled Mains Switch Circuit Diagram. Simple but very forkful project for audio liker circuit. This circuit will switch off the line supply to audio or video equipment if there has been no input signal for about 2 seconds. SI provides manual operation and S2 acts as a reset. This circuit allows for time to change a tape or compact disc.About 50 mV of audio signal is necessary. Read:  Solid-State Switch For Dc-Operated Gadgets

Audio Controlled Mains Switch Circuit Diagram

Sourced By : Circuitsstream

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Sound Operated Switch for Lamps Circuit Diagram

This inexpensive, fully transistorised switch is very sensitive to sound signals and turns on a lamp when you clap within 1.5 metres of the switch. One of its interesting applications is in discotheques, where lights could be turned on or off in sync with the music beats or clapping.

Sound-Operated Switch for Lamps Circuit Diagram

The condenser microphone senses the sound and converts it into electrical variations. The electrical signals are amplified by the two-stage direct-coupled (DC) amplifier formed by transistors T1 and T2 and fed to the switching circuit. The switching circuit comprises transistors T3, T4 and T5, which conduct only when the circuit senses sound signals. Transistor T5 supplies sufficient gate voltage to the triac to drive the 230V lamp.

The regulated 12V DC power supply for the circuit is derived from AC mains by using resistor R14, diode D1 and zener diode ZD1. The circuit can be assembled on any general-purpose PCB.

Soursed By: EFY: Author Pradeep G.

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Simple Touch Sensitive Switch Circuit Diagram

This is a Simple Touch Sensitive Switch Circuit Diagram. This circuit A high impedance input is provided by Ql, a general purpose field effect transistor 741 op amp is used as a sensitive voltage level switch which in turn operates the current Q2, a medium current PNP bipolar transistor, thereby energizing the relay which can be used to control equipment, alarms, etc.

Simple Touch Sensitive Switch Circuit Diagram

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