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.
We found this circuit in a 1982 publication. This transmitter sends its signal to any AM radio...
The oscillator shown in the figure generates a rectangular signal with a 50% active cycle (square)...
We found this range of LEDs with the UAA180 in the 1976 Siemens Integrated Circuits manual. The...