Eu posso ver uma luz verde no meu adaptador de laptop Dell, mesmo quando o adaptador está sendo usado e conectado a uma fonte de energia. De acordo com meu conhecimento, isso indica que o adaptador está conectado à fonte de alimentação e à energia de recepção. Ao desconectar o adaptador da minha fonte de alimentação, a luz verde continua a brilhar por cerca de 2 a 3 minutos. Alguém pode me explicar por que está brilhando mesmo quando a fonte de energia está desligada? o que está acontecendo no fundo?
Simplesmente, em uma PSU, existe um grande capacitor para nivelar a fonte de alimentação da sua máquina através do circuito do transformador.
Isso leva a um longo tempo de imersão para que a energia seja dissipada o suficiente após a desconexão da rede elétrica.
O poder não duraria muito tempo para carregar sua máquina, frações de segundo, talvez, mas é mais do que suficiente para manter o LED aceso por algum tempo após a desconexão.
Some light switches run a small amount of current through the bulbs even when off, usually to power small devices at the switch like a timer, motion sensor, or night light. Do your switches have either of those features, or something else like that?
The way those devices work is instead of having a hot/neutral pair powering the switch, they just sit inline with the hot wire and draw a very small amount of power. Old fashioned incandescent bulbs won't light up if there's only a small amount of electricity running through them, so you would never notice this current, but LEDs are much more efficient and apparently are getting enough power to run.
If that is the cause of the problem, there are a few solutions:
Swap out the light switches for regular ones. You'll lose whatever additional functionality they have. Upgrade your switches to ones that have both a neutral and a hot wire, instead of just the hot wire. This may be relativelystraightforward or extremely difficult, depending on whether the neutral for the light goes through the same box as the switch. (Note that even if you do have a neutral at the box it may be a little tricky to wire it up, since you'll have to cut it and then probably add a pigtail or two.) Put back your old-fashioned incandescents.
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If we're talking a high voltage circuit, w high intensity LEDs: Many high intensity white LED's use a phosphor that is in fact phosphorescent, like glow in the dark paint. You just have to wait for it to dim down. Switching to a different brand of bulb, with a different phosphor may help, but it's hard to "try before you buy".
If we're talking a low voltage circuit, 5-12v: A capacitor in line with an LED can power it for quite some time. You can limit this effect by by using a power supply with a smaller filter capacitor.
Ou é devido ao capacitor ( mais informações )
Tags laptop adapter power-supply