We found this circuit in a documentation for radio amateurs from the 70s. The transistors can be the BC548. With it, small speakers of 4 or 8 ohms can be used as microphones.
Found in a 1965 Electronic Design, this circuit generates adjustable pulses between 200 uA and 10...
We found this circuit in the 1982 SGS Linear Integrated Circuits manual. The transistor supports...
This circuit can equip the electronics practitioner's bench with an excellent number of resources. In...