Am Radio Transmitter Circuit Diagram

The oscillator is built around q1 and associated components.

Am radio transmitter circuit diagram. Original am micropower transmitter. This is the simple and low cost am transmitter schematic diagram built using transistor bc109c. The carrier wave is then amplified by the radio frequency rf power amplifier to the desired output wattage. Following the action in figure 6 the oscillator creates an ac sine wave at the desired frequency.

Follows fcc regulations and still produces enough amplitude modulation. It is illegal to operate a radio transmitter without a license in most countries. The tank circuit l1 and vc1 is tunable from about 500khz to 1600khz. This am radio transmitter can transmit audio sound to your backyard.

The transmitter legally operates with micro power and will not set any distance records but unlike simpler designs the frequency stays put and the fidelity is excellent. Low range am radio transmitter circuit diagram. This signal is called the carrier wave. A simple am transmitter circuit with diagram and schematic.

The oscillator is built around q1 and associated components. The picture to the left is a high quality radio transmitter for the a m. The circuit use a compact three transistor regenerative receiver with fixed feedback. This is the simple and low cost am transmitter schematic diagram built using transistor bc109c.

The circuit is in two halfs an audio amplifier and an rf oscillator. A condenser microphone is used for speaking. These components can be used from an old mw radio if available. The circuit is in two halfs an audio amplifier and an rf oscillator.

This ircuit is deliberately limited in power output but will provide amplitude modulation am of voice over the medium wave band. The tank circuit l1 and vc1 is tunable from about 500khz to 1600khz. Notes it is illegal to operatea radio transmitter without a license in most countries. Where resistors r1 and r2 are in ohms capacitor c1 is in microfarads and frequency f is in hertz.

This frequency can be changed by simply replacing r2 with a variable resistor or c1 with gang capacitors. All general purpose transistors should work in this circuit you can use bc549 transistors for this circuit. The audio output from condenser mic is preamplified by transistor t3 bc548. A block diagram representing various stages of a basic continuous wave radio transmitter.

The circuit is in two halfs an audio amplifier and an rf oscillator. This circuit is deliberately limited in power output but will provide amplitude modulation am of voice over the range 500khz to 1600khz with values shown. It is similar in principle to the zn414 radio. The audio output from t3 is further amplified by transistor t2 bd139 which modulates the rf amplifier built around transistor t1 by varying the current through it in accordance with the audio signal.

The am radio transmitter does not use any modulator transformer.