This circuit was found in a 1967 US documentation. The circuit applies to modern general purpose transistors. The circuit has no offset. The power supply must be symmetrical.
This circuit was found in Motorola documentation from 1966. The lamps are according to power and...
This circuit, which uses components still common today, was found in a 1997 documentation. It...
This circuit is intended to apply the music signal from a stereo to a telephone line for the...