De-engergizing a Capacitor

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=37113
Printed Date: May 10, 2025 at 8:50 PM

Topic: De-engergizing a Capacitor

Posted By: donnie5336
Subject: De-engergizing a Capacitor
Date Posted: August 10, 2004 at 10:42 AM

I am taking my system out of my car and I lost the resistor that came with my cap. How can I safely discharge it without one. If i disconnect my battery , can I see if the radio will still come on (being powered by the cap) and leave it turned down very low and let it drain my cap that way? or what??

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Donnie

Replies:

Posted By: xetmes
Date Posted: August 10, 2004 at 11:00 AM

just leave a light (like the domelight) on and disconnect the battery

Posted By: donnie5336
Date Posted: August 10, 2004 at 12:12 PM

I dont have my voltmeter here and i know energized caps are dangerous so i wanna make sure. if i disconnect the + of my battery and open my doors, the domelight slowly goes out. I have a digital display on my cap but it only comes on when the HU cuts on. When the lights slowly dim like that when i disconnect the battery, can i assume that teh cap has discharged?

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Donnie

Posted By: donnie5336
Date Posted: August 10, 2004 at 12:41 PM

anybody???

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Donnie

Posted By: xetmes
Date Posted: August 10, 2004 at 12:54 PM

yea its discharged, leave it sit for a few min after the light goes out if you are really paranoid posted_image

Posted By: donnie5336
Date Posted: August 10, 2004 at 12:59 PM

thanx

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Donnie

Posted By: flynntech
Date Posted: August 11, 2004 at 12:41 AM

stick a screw driver between the terminals.....

NO, just kidding!!!

My boss told me to test batteries like this when I worked a junkyard! This guy was an idiot, he was a typical kneck. He scratched his head at the site of my multimeter, yet thought nothing of arc welding the mechanic's $60 snap-on screwdriver to some old battery lying in the dirt! ...So glad I can look back and laugh at these things.

Posted By: flynntech
Date Posted: August 11, 2004 at 12:43 AM

If your dome lights are out and your battery is disconnected, what would the voltmeter read?

.........ahhhh!

Posted By: donnie5336
Date Posted: August 11, 2004 at 11:46 AM

haha lol thanx . I got it. I was pretty sure that would work but i was doing something at my fuse block once and forgot about the cap.. i was thinking only one side of the block was hot with my fuse out... ouch.

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Donnie

Posted By: delphidoc
Date Posted: August 11, 2004 at 11:39 PM

Here's three links on capacitor discharging. The sites are related to appliances, but it applies to all capacitors:

https://www.gallawa.com/microtech/safety.html

https://www.ehow.com/how_16749_discharge-capacitor.html

This next one is the best: https://fixitnow.com/2003/06/mailbag-discharging-and-testing.htm

because Samurai Appliance Repair Man has his own forum with entertaining stuff like this:

https://www.fixitnow.com/forumfools.htm

Enjoy. posted_image

Posted By: MBZ oe
Date Posted: August 15, 2004 at 5:34 PM

500ohm resistor

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BOOM, BOOM, BOOM BOOM....