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.
With this simple tester you can measure the gain of an NPN or PNP transistor. The instrument can...
I found this circuit in an old Argentine publication from 1973. The components are no longer...
Used with telephones at the time, this circuit was found in Popular Electronics from the 90s. The...