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 is interesting for applications that are powered by batteries and need constant...
This circuit is indicated to operation with piezoeletric transdicers or other with high impedance...
This mouse circuit was found in the January 1997 issue of Electronics Now magazine. It uses a PIC...