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.
Twin-T oscillator are designed to produce sine low frequency signals. These oscillator are...
This circuit keeps an LED on briefly when S1 is pressed. The time depends on C1. The circuit is...
This stage was used in old audio ampliiers and radios from the 1950s and 1960s. It uses one of the...