We found this circuit in documentation from the 1980s. The transformer is of the low voltage type with a 1: 3 turn ratio and the transistors can be of general-purpose types.
This circuit was found in a 2005 Linear Technology documentation. The circuit is based on LTC4213...
This wired intercom was found in a 1960 Sylvania transistor manual. The transformers are the type...
We found this circuit in a Japanese publication from the 1960s. The frequency depends on the coil,...