This simple TTL siren was found in a 1980s Electronics Today International. The power supply is 5 V and the integrated circuit can be the 7400.
This circuit for loads up to 10 A was found in a 2005 Linear Technology documentation. The MOSFET...
In this circuit of a 1956 publication, the handset must be high-impedance magnetic and L1 has 200...
This circuit can be used to obtain a zener voltage from a common zener of another value, adjusting...