This amplified metronome was found in a 90s Popular Electronics. The circuit is powered by a 9 V battery but will also work with 6 V of 4 standard batteries.
We found this circuit in a publication for radio amateurs in 1974. The bipolar transistors can be...
Found in a 1980s American documentation, this circuit has a current consumption of only 1 mA. The...
This adjustable power supply was found in Ferranti's transistor manual from 1974. Power...