FM Transmitter Bug Circuit

Posted by Micro System

on Sunday, September 5, 2010

This is a circuit for transmitter that can be used for FM. This is the figure of the circuit;

 

This circuit is small transmitter uses a hartley type oscillator. Normally the capacitor in the tank circuit would connect at the base of the transistor, but at VHF the base emitter capacitance of the transistor acts as a short circuit, so in effect, it still is. The coil is four turns of 18swg wire wound around a quarter inch former. The aerial tap is about one and a half turns from the supply end. Audio sensitivity is very good when used with an ECM type microphone insert

Full Wave Bridge Rectifier Circuit

Posted by Micro System

on Monday, July 26, 2010

This is a design circuit for full wave rectifier. This circuit is a simple form. In this circuit is need Low-voltage AC power supply (6 volt output). This circuit provides full-wave rectification without the necessity of a center-tapped transformer. In applications where a center-tapped, or split-phase, source is unavailable, this is the only practical method of full-wave rectification. This is the figure of the circuit;


In addition to requiring more diodes than the center-tap circuit, the full-wave bridge suffers a slight performance disadvantage as well: the additional voltage drop caused by current having to go through two diodes in each half-cycle rather than through only one. With a low-voltage source such as the one you're using (6 volts RMS), this disadvantage is easily measured. Compare the DC voltage reading across the motor terminals with the reading obtained from the last experiment, given the same AC power supply and the same motor.