Like the previous circuits, this one uses a small speaker as a microphone and has two amplification stages with 600-ohm output.
This circuit is from old documentation, which means that the operational used is not easy to...
Two tone siren (CB9085E) This circuit was found in a 1980’s Radio Electronics. The signal must be...
Based on Texas Instruments documentation, this circuit is based on the BQ2000 a circuit used to...