Author Topic: Should I power a device with the leads hooked up backwards on the power supply?  (Read 543 times)

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Offline duckduck

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POP!

No. No, I should not.

EDIT:

So, to further publicly humiliate myself. I should mention that this is the SECOND one of these ICL8038-based signal generators that I have accidentally destroyed using this method. The first one I put down to "damn cheap crap off of Amazon". In both cases I ignored the warning flag of the amperage ramping up scary fast as I rolled up the supply voltage to the spec of 12-15 volts DC. Turns out a small IC and supporting components doesn't consume 2,000mA @ 12V. Who knew?

I swapped the leads on the power supply (noting the handy + and - symbols printed above the terminals) and, amazingly, the signal generator outputs a nice square wave. The sine wave had a triangular top but seemed kinda OK otherwise. I've ordered a third one.  :palm:

EDIT EDIT:

You often learn valuable lessons from your mistakes!

Indeed, nothing like a good old-fashioned public shaming to burn that lesson in. If I can serve as a negative example and/or reminder to others, so much the better.

EDIT EDIT EDIT:

Now I where saftey glasses ,  double check and look away on first power up when ever a cap is changed .

Yes, that cap cap shot up like a little bullet. I'm going to leave a pair of safety glasses at my electronics desk. Thanks for the suggestion.
« Last Edit: April 16, 2021, 04:01:11 pm by duckduck »
 
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Offline harerod

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R5 seems to have gone high impedance...
Before you speak, let your words pass through three gates: At the first gate, ask yourself “Is is true?” At the second gate ask, “Is it necessary?” At the third gate ask, “Is it kind?” – Rumi
 
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Offline schmitt trigger

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Were you able to catch some of the magic smoke before it flew away?
 

Online bobbydazzler

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Did R5 melt?
 

Offline srb1954

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You often learn valuable lessons from your mistakes!

The shock of an electrolytic capacitor exploding in your face is the best way to learn that you always need to check the polarity of your power supply leads before switching on.
 
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Offline ledtester

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This XR2206 kit has a diode, but I don't think it was drawn correctly in the schematic:

[attach=1]

More details:

- https://rhelectronics.net/store/function-generator-xr2206-diy-kit-20hz-100khz.html
- Kit PDF manual: https://ln.sync.com/dl/80dc9e630/9u9yqjmr-72bk4qs8-93geqv9y-td7zxkfa
 

Online Ed.Kloonk

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Were you able to catch some of the magic smoke before it flew away?

Have you ever noticed that the eye socket is the perfect size and shape for catching flying capacitors? Hold the tongue right.
 

Offline Jwillis

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Have you ever noticed that the eye socket is the perfect size and shape for catching flying capacitors? Hold the tongue right.

I know all about that . I had a 13 x 25mm blew off the board like a bullet and struck me just on the lower edge of the left eye socket . Doctor said that if it was 5mm higher I would have lost the eye . Now theirs a permanent scare where the stitches were and I lost some peripheral vision .

Cause was an incorrect polarity . Now I where saftey glasses ,  double check and look away on first power up when ever a cap is changed .

Please be careful .
 
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