Power Supply 2.0. This version uses only one transformer. It is a 25.2 volt CT at 100 mA or higher. Or use a 24 volt CT at 100 mA or higher. Most likely you will only be able to find 1 amp versions of this transformer. The lower prong of the power plug goes through the lower pole of the switch and to the bottom end of the transformer primary. The upper prong goes through the upper pole of the switch then through a 1/4 amp fuse to the top end of the primary. This transformer has one secondary. It is center tapped and the tap goes to ground. The two ends of the secondary connect to the AC inputs of a bridge rectifier. General purpose 100 volt 1 amp. The AC inputs are where the anode of one diode connects to the cathode of another diode. The positive output of the bridge, where two diode cathodes connect together, gos to the positive end of a 1000 u f 25 volt capacitor. The negative end goes to ground. The positive end of the cap goes to the input terminal of a 7812 positive 12 volt T O 220 regulator. The common terminal goes to ground. The output terminal goes to plus 12 volts. There are two 0.1 u f capacitors mounted physically close to the regulator. One connects from the input to ground and the other connects from the output to ground. I don't care what the data sheets say. If these capacitors are omitted the regulator will oscillate in the neighborhood of 1 MHz. The negative output of the bridge, point where two diode anodes connect together, goes to the negative terminal of another 1000 u f capacitor. The positive end is grounded. The negative end of the cap goes to the input terminal of a 79L12 negative 12 volt T O 92 regulator. The common terminal goes to ground. The output terminal goes to minus 12 volts. This regulator has two 0.1 u f capacitors connected from input to ground and output to bround in the same way and for the same reason as with the positive regulator. In addition an L E D has its anode grounded. The cathode goes through a 1 k ohm 1/2 watt resistor to the negative output terminal of the bridge rectifier. This completes the verbal description.
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