In fact, what this circuit does is work the two channels of a stereo system producing two additional channels. Thus, the system becomes a 4-channel system for home theater, for example. The idea can be worked out to use any operational.
This circuit is from an 1977 American publication. The coil consists of 30 + 70 turns of 28 AWG...
LEDs are diodes and can be tested with a simple configuration that allows the display of its...
This circuit using components that are still common in our market was found in a 1987...