ELi5: Why do you need to wait 10 seconds to power cycle certain electronics?
In: Technology
Lots of power supplies use capacitors for filtering amongst other things. They need to bleed down their stored charge otherwise the power reset may not be effective. 10 seconds is insufficient in many cases in my experience.
Electronics use capacitors, which store a small amount of charge. Some (probably most) electronic devices have capacitors that are sufficiently large that they can continue to power the device for a few seconds after you have turned them off.
This means that if you switch an electronic device off then on again immediately, the capacitors may keep the electronics running right through your attempt to power cycle them.
Have you noticed how on many devices that have a small “power on” LED, it doesn’t go out immediately you turn the device off but rather stays on then fades out? Same thing – capacitors are continuing to power the LED for a few seconds, till they run down.
Electrical items have capacitors that hold a charge even after power is off. The time delay lets this charge dissipate to have a true reset.
For most consumer-facing electronics, one second is likely enough, but technicians will tell you ten seconds to make it clear that there needs to be *some* adequate time to discharge. Think, for example, of devices you own that don’t completely reset when your home’s power flickers.
My post was deleted because apparently just telling you that the answer is capacitors is not enough.
So as an eli5:
There’s these special parts that can store energy for temporary lengths of time. Kinda like batteries but not really, they take electricity and slow it down so that it takes a long time to travel. This allows enough energy to be available at all times.
But what this means for restarting electronics from boot means that to make sure all lasting energy is consumed, you should wait a short period before turning your equipment back on.
Electronics use capacitors, which are essentially little batteries, when you turn things off those batteries will keep it powered for a few seconds, or in the case of some equipment a few minutes.
In essence when turning something off you switch it to a very limited battery backup.
I work in industrial controls, big inverters with huge smoothing capacitors, if you’re working on those, you turn them off completely and go for a coffee to allow the caps to bleed down if you don’t they’re capable of giving you a horrific bite, some of the smaller inverters will take up to 45 seconds to finally turn off totally after power is off.
Think of turning a garden hose off. The valve is way back at the house and you have varying length of hose. If it’s 25ft of hose then it will empty out faster than 100ft of hose. If you’re talking about instructions to wait 30 seconds, that’s probably way more than necessary, but getting a good reset is essential when troubleshooting to dump anything bad in short term memory.
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