Found in a 90s Popular Electronics, this circuit is based on a common CMOS component. The circuit triggers a buzzer by approaching objects from an antenna.
This circuit was found in a Mullard transistor manual from 1960. Note the symmetrical power...
This amplifier step with a transistor has an input impedance of 100k to 10 M. The transistor can be any...
I found this little signaling transmitter in old American documentation. The circuit has a good...