We found this circuit in the 1990 Philips Databook. The circuit is a commercial application of the decoder in stereo FM radio receivers.
This light-controlled circuit uses a 6 V or 12 V relay depending on the supply. The transistor can be the...
This circuit was found in the March 1999 issue of Electronics Now magazine. The meter is analog and...
This preamp with a transistor for turntables with crystal capsules was found in a Japanese...