This an old commercial receiver found in a year 1958 magazine. The circuit uses some transformer available that timer and the transistors are germanium types. The circuit is intended to receive MW stations.
This line protector circuit was found in a 2002 documentation, but it is totally current and...
Using CMOS circuits and operational amplifiers of the time, this circuit was found in the...
This circuit was found in a 1980s US publication. It indicates when the phone is off-hook by...