A vintage Radio Shack variable power supply #ShackToberFest
I picked up this Radio Shack Micronta variable power supply in the late 1980s. I mainly needed a clean source of 5v for logic projects.
It can supply 0-25 volts at up to 1 amp (internally limited the back says).
The analog meter shows both voltage and current, switchable on the front panel. And that bit me once. I was making a pulse detection circuit for a rotary phone that didn’t seem to work. The switch was set to amps and was reading zero and I naiively thought it was at zero volts and cranked it up. I fried my logic chips. I didn’t remake the circuit.
I did make a couple of different leads. One is banana jacks to alligator clips.
I still even have the box and paperwork (amazingly) but those are in storage so I didn’t photograph them.
Did you have vintage Radio Shack gear? Let us know in the comments.
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The MicrontIa 22-123 (Radio Shack) Variable DC Power has been and remains one of the most useful power supplies ever made. Normally considered zero (0) to twenty four (24) volts adjustable output, the current will auto limit at about 1.2 amps (from memory). I scanned the manual to PDF and have posted it to a number of wet sites. You can always reach out direct to me for a copy.
This supply is one of the best low voltage applications of the classic LM-723 chip driving a pass transistor system/circuit. The designers did it correct by including a negative rail (voltage), allowing full zero to full output. A lot supplies including those made with LM-317 type three terminal regulators, don't operate well from zero to about 3 or 4 volts without a negative reference (doesn't have to be a full supply). The only other supply like this I've seen with the negative offset not being a separate supply, is an Elenco (also a nice supply).
The 22-123 Variable DC Supply will self limit, which is incredibly handy. You'd be hard pressed to kill the supply, I've not been able to hurt one yet… There are other similar versions of this supply, originally sold by Radio Shack. Early versions include a dual output 22-121 and even the 22-126. Ebay is a great place to see and possibly pick one of these work horse supplies up for your work space.
The MicrontIa 22-123 (Radio Shack) Variable DC Power has been and remains one of the most useful power supplies ever made. Normally considered zero (0) to twenty four (24) volts adjustable output, the current will auto limit at about 1.2 amps (from memory). I scanned the manual to PDF and have posted it to a number of wet sites. You can always reach out direct to me for a copy.
This supply is one of the best low voltage applications of the classic LM-723 chip driving a pass transistor system/circuit. The designers did it correct by including a negative rail (voltage), allowing full zero to full output. A lot supplies including those made with LM-317 type three terminal regulators, don't operate well from zero to about 3 or 4 volts without a negative reference (doesn't have to be a full supply). The only other supply like this I've seen with the negative offset not being a separate supply, is an Elenco (also a nice supply).
The 22-123 Variable DC Supply will self limit, which is incredibly handy. You'd be hard pressed to kill the supply, I've not been able to hurt one yet… There are other similar versions of this supply, originally sold by Radio Shack. Early versions include a dual output 22-121 and even the 22-126. Ebay is a great place to see and possibly pick one of these work horse supplies up for your work space.