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Getting a shock from band new capacitors

xoaphexox

xoaphexox

Supernatural Anesthetist
Okay, so today another box of capacitors came from Digikey as they often do around here, but I witnessed something that I did not think was possible.

I removed two 12000uf 63V Panasonic T-HA capacitors from their shrink wrapped plastic baggies and set them on the floor as I continued to take inventory. Then what happened really surprised me - one of them fell over, making contact with the other and two sparks flew and it sounded like I had dropped a pair of dice on a concrete floor.

I was amazed! I did not know that "new" capacitors came with a charge in them? Is this so?!

:scratch2:
 
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I think you charged them up a little when you were taking them out of the plastic.
 
xoaphexox said:
Okay, so today another box of capacitors came from Digikey as they often do around here, but I witnessed something that I did not think was possible.

I removed two 12000uf 63V Panasonic T-HA capacitors from their shrink wrapped plastic baggies and set them on the floor as I continued to take inventory. Then what happened really surprised me - one of them fell over, making contact with the other and two sparks flew and it sounded like I had dropped a pair of dice on a concrete floor.

I was amazed! I did not know that "new" capacitors came with a charge in them? Is this so?!

:scratch2:
Click to expand...

It's MAGIC.

OK probably not.
 
Either way, I just slapped those puppies in the Pioneer SA-8800 on the bench and now its fully recapped and singing like anything!

Even though I think I am getting pretty good at this recapping thing I still cover my ears when I initially turn the units on - all it took was one cap exploding about 4 months ago to scar me for life :sigh:
 
xoaphexox said:
...

I was amazed! I did not know that "new" capacitors came with a charge in them? Is this so?!
Click to expand...
New capacitors, tested at the factory, low leakage -> all these factors combined.

OTOH old capacitors from 6~10 years ago that were kept in storage unused should be "reformed" for a few minutes before installing in final circuit.
 
Gigapod said:
New capacitors, tested at the factory, low leakage -> all these factors combined.

OTOH old capacitors from 6~10 years ago that were kept in storage unused should be "reformed" for a few minutes before installing in final circuit.
Click to expand...

Reformed? How?
 
Electrolyitcs have a relatively high dielectric assorbtion. Take a 10,000mfd cap and charge it up close to it's rating. Discharge it quickly with a light bulb while keeping the meter attached. When the bulb is removed you'll see the cap voltage creep back up a few volts. That's why you get the spark. it's not uncommon to see 5-10 volts on a big electrolytic.
 
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