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.
Suggested by an American technical documentation, this circuit is polarized in order to provide an...
This modulated siren was found in the December 1974 issue of Radio Electronics magazine. A higher...
This circuit with 5 times gain was found in European documentation from the 1980s. The input and...