Reversed Electrolytics redux
dave.g4ugm at gmail.com
Sat Aug 22 18:19:37 CDT 2015
> Also, I now know why the +5 V is high. It has a UA 7805 3 terminal
> serving as a voltage reference for a TIP-3055 so the supply can provide
> current. That 7805 has a forward biased diode between the center terminal
> and ground, thus raising the output voltage by right around 0.5v. I
> will leave it alone.
When used as series pass transistor the TIP-3055 will usually drop 0.6v
across the emitter under any significant load. Adding a silicon diode in the
7805 base is the normal fix...
> The same design is used for the +24V, which comes out at 24.2V.
> So, odds are that this supply could drive two floppy drives.
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