Members of Elektor’s global community of professional engineers, electronics engineering students, academics, and makers welcome the chance to learn from their engineering mistakes. Petros Perdikouris, a Piraeus, Greece-based mechanical engineer, recently told us about his experience with fried op-amps — and a hurt finger.  
An op-amp as a buffer amplifier. Read
B. Kainka's article "Operational Amplifiers
in Practice" (Elektor Nov/Dec 2018).

Fried Op-Amps

“I was making one small circuit with two op-amps (ESD sensitive) and one DC-DC converter as a power supply to convert 24V DC to ±15V for the op-amps. I assembled the circuit on a breadboard, put the op-amps and tested it. It was working fine. The DC-DC converter manual stated that it did not need any capacitors at the input and outputs, but putting some was not a bad idea, so I decided to solder three electrolytic capacitors — one on the input and two at the outputs. After soldering, hell broke loose! The power supply was showing almost 100 mA of amperage! I had a short circuit somewhere!
 
Checking the board did not show something, but what? One op-amp burnt my finger! I changed the op-amp, no short circuit, but the circuit was not working. After some research, I decided to change the other op-amp as well and then ... everything fine!
 
I suppose that putting the capacitors and/or touching the circuit with my soldering iron fried the two op-amps. I never thought to remove the ICs when doing these kinds of changes on the circuit board. Anyway, now I know!” – Petros Perdikouris

More on Op-Amps

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