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.
This circuit was obtained in an 1975 English publication. It is a voltage regulator circuit for...
In the figure we have an infrared receiver circuit using an operational 741. The circuit is an...
This circuit is suggested by National Semiconductor and makes use of the negative regulator LM2990...