Very low power, power supply

I read in sci.electronics.design that Rich Grise wrote (in ) about 'Very low power, power supply', on Fri, 18 Mar 2005:

Nah! You can always repair the broken heater coil with a bit of Al foil. (;-)

Or toast one slice at a time.

Not for long enough to matter. Besides, at the first failure the circuit will no longer meet its specifications for total light output making the whole thing delared broken. People rarely keep a toaster that will only toast one of the two slices.

I've broken a LED or two in my life. They tend to turn into low value resistors at low amounts of destruction. You have to do something fairly major to make the part go open. Merely running some 20-40mA through them backwards is not nearly major enough.

They are typically rated for 5V backwards but may not break down until perhaps as much as 10V. 40mA times 10V is only 0.4W. That will not cause any sort of "BOOM".

It gives you less flicker at the cost of a bridge rectifier. The bridge costs money to install and also has a failure rate so it increases the chance of failure.

If you really care about the flicker, adding another capacitor can reduce it.

Hi Ken,

Ken Smith schrieb:

It isn't entirely. 3 LEDs are still working!

Using your circuit, there will be no LEDs that are still working.

How can you tell that? Any sources?

Yes, thats true.

Also, using a bridge rectifier gives you the advantage of less flicker (120Hz) for all 6 LEDs. Your suggestion will flicker with 60Hz alternatively.

Regards, Wolfgang

I understand that to wish to use LEDs. You probably have reasons for choosing that particular light source, and I'm not going to try to convince you otherwise. But have you considered electrolumenescent strip? They (some of them?) can connect directly to the mains. They come in a variety of shapes and sizes (sq. inches/cm), come in several colors including white, draw very little current, are long lived, and are available on the surplus market at prices that are competitive with - or less than - a white LED solution.

Someone else mentioned that but form the little looking I did, it sounds like I wouldn't get near as much light as I would from 6 white LEDs. From what I understand, at the 60hz signal I plan on connecting to, this stuff isn't very bright. Can you tell me about how much of it I would need to equal 6 white LEDs? I didn't pick white because of brightness, I do not want a colored light.

In article , Watson A.Name - \"Watt Sun, the Dark Remover\" wrote: [...]

As it gets hotter, the voltage decreases.