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.
Found in a 1970 EEE, this circuit uses general-purpose transistors of the time. Transistors support...
In the figure we have a simple signal tracer circuit to be coupled to the volume control of an AM...
This is a small audio amplifier for headphones for experimental receivers. The transistor can be...