Author Topic: On/Off switch required ?  (Read 884 times)

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Offline Jan AudioTopic starter

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On/Off switch required ?
« on: April 22, 2020, 01:54:34 pm »
Hi, i make my projects without on off button normally, is it bad for capacitors ?
The capacitor loses - connection while still being full when pulling the powersupply.

Does it affect the lifespan of capacitors ?
Maybe i need to add power button for my next project.

thanks
 

Offline Vovk_Z

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Re: On/Off switch required ?
« Reply #1 on: April 22, 2020, 03:21:57 pm »
Sorry, it's almost totally unclear what do you mean. You don't want to turn off power switch?
Electrolytic capacitors age with time and age with work and age a lot with heavy work.
 

Offline Jan AudioTopic starter

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Re: On/Off switch required ?
« Reply #2 on: April 22, 2020, 04:03:09 pm »
When powering down i remove the power supply, is it bad for the elkos ?
Or do i need a on/off button that makes sure the ground stays connected while the elko is still full ?
 

Offline Cubdriver

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Re: On/Off switch required ?
« Reply #3 on: April 23, 2020, 07:24:56 am »
Still not quite following you.  By 'remove the power supply' do you mean like unplugging or disconnecting the AC mains cable feeding the power supply built into the device, or are you talking about removing power from a device that's fed by a mains powered DC supply (like a wall wart or brick) by unplugging the DC feed from that power supply o the project?

Where are the electrolytics you're concerned about - in the project that's been disconnected from the D.C. power source, or in the output of the D.C. power source that you're disconnecting?

-Pat
If it jams, force it.  If it breaks, you needed a new one anyway...
 

Offline Jan AudioTopic starter

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Re: On/Off switch required ?
« Reply #4 on: April 23, 2020, 01:20:20 pm »
I learned that the higher voltage on the cap always should be on the + else it is bad and you have to replace the cap.
If the cap is still full and both + and - are disconnedted, how does the cap know it is higher then the - ?
How can i explain ?
 

Offline squarefrustration

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Re: On/Off switch required ?
« Reply #5 on: April 23, 2020, 02:06:40 pm »
I learned that the higher voltage on the cap always should be on the + else it is bad and you have to replace the cap.
If the cap is still full and both + and - are disconnedted, how does the cap know it is higher then the - ?
How can i explain ?

A capacitor holds charge. The polarity of that charge is determined by the circuit that it is placed in. If you remove the power input to your circuit, the capacitor will not become "confused". The charge polarity will remain the same as it was the moment power was disconnected, and it will discharge to zero at a rate determined by the load it is attached to (as well as it's own leakage). Think of it like a battery. When you have a battery that is not in a circuit, it does not need to "know" which side is positive or negative. Conversely, many devices do not have an on/off switch, such as power supply "bricks" for laptops and phones. When you unplug these devices, the DC filter capacitors drain through the circuit that is loading them. Hope that helps!
« Last Edit: April 23, 2020, 02:08:42 pm by squarefrustration »
 


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