The resistors R1 and R2 consist of 8 220 ohms x 2 W resistors connected in parallel. The dissipation must be higher for high transmitter power. The indicator can be the multimeter.
This circuit with only one transistor was obtained in an old English documentation and can be...
This circuit uses a transistor as noise source and a 741 IC as amplifier, sourcing a high...
This circuit uses an LED (called SSL) to regulate current in a configuration with complementary...