This 3-tube receiver is from a 1924 publication. The circuit has 3 supply voltages and a high-impedance headphone output.
We found this simple alarm circuit in a 1981 documentation. As we can see, it is a car alarm...
We found this circuit in an English magazine from 1976. The magazine no longer exists, but just...
Suggested by General Electric in a 1968 documentation this integrated amplifier uses a component of...