This variable frequency circuit was found in a Popular Electronics from the 90s. The circuit outputs to a small speaker and can be powered by voltages as low as 3 V.
This circuit is suitable for applications such as a TTL log digital link. Maximum frequency is...
We found this simple wired intercom circuit with transistors in a 1988 publication. In addition to not...
Other operational amplifiers can be used on this unit gain amplifier. The circuit is from the 1993...