AC to DC to more DC

Some coworkers are trying to write a computer program to control the effusion cell shutters on their growth chamber. Unfortunately, the computer output we have can only put out 5 Vdc, and the shutter box needs 13.5 Vdc to actuate and so they asked me to build them a box to upconvert between the two. The catch was that it couldn't run on battery power, it needed to run off the line--and I'd never done that before.

The circuit to multiply a DC voltage is farily simple, but they needed eight channels for the eight shutters, and I decided to go all out and add a cooling fan and power LED. To save time (and possibly, injury) I decided to buy a ready made power entry module--with built in RF filter, fuse box and switch--and regulated power supply--the transformer that turns the AC line voltage into the DC to power the circuit. The power supply is awesome because it's called the Power Gorilla, and it has a picture of a gorilla. Yeah, it's made in japan...

Wired circuit board--with POWER GORILLA!


Near complete box.

Assembled DC Converter.

Of course, in the long tradition of homemade electronics, it didn't really work the first time. It turned on ok, the fan and LED worked, and--most importantly--no one died and nothing caught on fire. But there was a fatal design flaw, the resistors I chose were two small, and so the op-amps could not put out enough current to generate the required 13.5 V. Luckily, it's fallen to Allison to replace all 24 resistors for me.

-Tim