TDA7000 Single Chip FM Radio

This fm radio series fm radio receiver circuit that uses a single ic TDA.

Quite easy to make this fm radio circuit, where all functions can be done by IC TDA, so we only add to the technical components only. External components are intended to support so you can determine its own range of frequencies to be used. Actually if you want to have the radio equipment are satisfactory you can buy a radio market. Now this type of radio is very varied and the prices varying as well. To be sure with the money of 30 thousand you can get the fm radio with satisfactory quality. Because now the most sold radio is using digital functions, unlike the more dominant is the first transistor radio. But if you are a hobby with experimental electronics, not the rupiah value but which you consider the value of their knowledge.

For the working principle of this circuit does not really exist that must be addressed because all the functions already performed by the internal circuit is ic TDA. That if we do a surgical series is in the ic, the result will not be much different circuits fm radio receiver in general.

Component List:

1. IC TDA 7000

2. Resistor: 100 Kohm, 22 Kohm 100 Kohm and potensio

3. Capacitors: 39 pF, 37 pF, 220 nF, 22 nF, 10 nF, 180 pF, 150 pF, 100 nF, 330 pF, 220 pF, 3.3 nF, 330 pF, 3.3 pF, 220 nF, 1.8 nF, 1.8 nF, 25-50 pF

4. Inductors: 56 NH (2 pieces)

5. Loudspeaker

6. Antenna

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Rugged PSU For Ham Radio Transceivers

This rugged power supply is based on the popular LM338 3-pin voltage regulator. The LM338 is capable of supplying 5 A over an output voltage range of 1.2 V to 32 V with all standard protections like overload, thermal shutdown, over-current, internal limit, etc., built in. In this power supply, some extra protections have been added to make it particularly suitable for use with low to medium-power portable and mobile VHF/UHF (ham) and 27 MHz transceivers. Diodes D4 and D5 provide a discharge path for capacitors C1 and C2. Diode D8 protects the supply against reverse polarity being applied to the output terminals. Capacitor C1 assists in RF decoupling and also increases the ripple rejection from 60 dB to about 86 dB.


If junction R1-R2 is not grounded by switch S1A, transistor T2 starts to conduct, causing the regulator to switch to zener diode D7 for its reference voltage (13 V). The PSU output voltage will then be 12.3 V. Normally, T2 will be off, however, and the PSU output voltage is then about 8.8 V. The high/low switch is useful to control the RF power level of modern VHF/UHF handhelds. Transistor T1, a p-n-p type BC557, acts as a blown-fuse sensor. When fuse F1 melts, T1 starts to conduct, causing LED D6 to light. If, for whatever reason, the PSU output voltage exceeds about 15 V, thyristor THR1 is triggered (typically in less than a microsecond).

Such a high-speed ‘crowbar’ may look like a drastic measure, but remember that this kind of protection is required by digital ICs that will not stand much overvoltage. The crowbar, when actuated, will faithfully destroy fuse F1 rather than allow the PSU to destroy expensive ICs. The two LEDs on the S1B contacts not only act as ‘high/low’ indicators but also as power-on indicators which are turned off when the mains voltage drops below about 160 V. If you envisage ‘heavy-duty’ use of the PSU, then voltage regulator IC1 should be mounted on as large a heatsink as you can get. The minimum we’d say is an SK129 heatsink from Fischer (Dau Components).

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