3 Channel Color Organ

The ac line power is brought back into the circuit through F1, a protective 5-A fuse. One side of the ac line is connected to one side of each ac outlet. The other side of the ac line is connected to each SCR or silicon-controlled rectifier. Each SCR is, in turn, connected to the other side of each ac outlet. An audio signal is brought into the circuit from a stereo speaker by transformer T1. This transformer has 500-ohm impedance on the primary and 8-ohm impedance on its secondary. Connect T1 so that the 8-ohm side is connected to the speaker and the 500-ohm side is connected to potentiometer P1. Potentiometer P1 is used as a level or sensitivity control. The signal from its wiper lead is applied to each RC filter stage. Because each SCR has a different RC (resistor/capacitor) filter on its gate lead, each will respond to different frequencies. The greater the capacitance in the filter, the lower the frequency that the SCR will respond
to.

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