Input Current Sensor (CB5409E)

This circuit is from 2005 Linear Technology documentation. The circuit applies to 12 V systems and is based on components of the time.

Two Transistor Adjustable Siren (CB1484E)
This circuit was published in a 1977 Radio Shack catalog. The PNP transistor may be BD135 and NPN...
Texas Instruments Standard Operational Amplifiers
Texas Instruments Standard Operational Amplifiers Texas Instruments makes available through Mouser...
Buzzer (CB6002E)
This circuit produces an intermittent ring tone being triggered directly by the telephone line. However,...