am transmitter circuits


Posted on Feb 7, 2014

The AM Transmitter circuits in two and a half, audio amplifier and an RF oscillator. The oscillator is built around Q1 and associated components. Tank circuit L1 and VC1 is melodious from about 500kHz to 1600KHz. These components can be used from an old MW radio, if available. Needs Q1 regenerative feedback to oscillate and this is achieved by con


am transmitter circuits
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necting the base and collector of Q1 to the opposite end of the tank circuit. 1nF capacitor C7, the signal pair from the bottom to the top of L1, and C2, 100pF ensures that the oscillation is passed from collector to emitter, and through the internal base emitter resistance of transistors, back to base again. R2 has an important role in this series. Ensure that the oscillations will not be pushed to the ground through the emitter is very low internal resistance, returning from Q1, and also increases the input impedance so that the modulating signal will not be encouraged. Oscillation frequency is adjusted with VC1. The following is a schematic drawing: Q2 is the cable as a common emitter amplifier, C5 decoupling the emitter resistor and realize the full benefits of this phase. Electric condenser microphone is mic and the amount of AM modulation is adjusted with the 4. 7k preset resistor P1. The antenna is not needed, but 30cm of wire can be used on the collector to increase transmitter range.




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