This circuit detects when a signal reaches its peak value. The source must be symmetrical and equivalent operational amplifiers can be used. This circuit was found in an old European publication.
This simple neon lamp power indicator circuit was found in the January 1971 Radio Electronics...
This elementary receiver with only one germanium transistor was found in a Japanese publication from the...
This simple 1 transistor circuit was found in an American documentation from the 60's. The...