Extreme Circuits

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Simple AM Transmitter

There are not many AM transmitters that are easier to build than this one because the inductor is not tapped and has a single winding. There is no need to wind the inductor as it is a readily available RF choke (eg, Jaycar Cat LF-1536). To make the circuit as small as possible, the conventional tuning capacitor has been dispensed with and fixed 220pF capacitors used instead. To tune it to a particular frequency, reduce one or both of the 220pF capacitors to raise the frequency or add capacitance in parallel to lower the frequency. Q1 is biased with a 1MO resistor to give a high input impedance and this allows the use of a crystal ear piece as a low cost microphone.
Simple AM Transmitter Circuit Diagram

Simple AM Transmitter Circuit Diagram

Tags: AM, transmitter, RF transmitter,

Comments on this post:

Nikoloz Glonti

1 year ago:  does anyone checked this circuit?!
on what frequency works this?

Seth Francis Solis

1 year ago:  how many turns in inductor(150uH) ?? ty

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