Indicated for activation by microcontrollers, this circuit was found in the Radio Electronics magazine of December 1987. The MOSFET can be of any type according to the buzzer.
This circuit was found in a 1992 documentation. It uses a photo diode as a receiver and an...
We found this circuit in an Australian publication from 1991. The circuit has good sensitivity, presenting...
The frequency of this oscillator depends on the coil and the 10 nF capacitor. The circuit is from...