small micropower control circuits

[iFred]

These are my circuits. One circuit uses PNP transistors, the other uses NPN.

After ordering so many solar cells, I had to do something with the broken cells, so here is my solution to the problem. I am cutting the cells with a diamond pen. and hooking them in series to produce enough voltage to recharge batterys.

These circuits are for use in very small power applications. Intended originally for small solar cells hooked in series, the idea was that as the cells charge the battery the LED (in my case night light ;-) would be off. As the cells get less light the bias resistor allows current flow and turns on the LED at night.

I have not tried it with a small size wind generator, however I think with a slight amount of adjustment to the circuit even a small microgenerator can be used to keep the rechargeable cells charged and turn the LED on only at night after a good recharge.

Good Luck!

Fred

[juiced]

Hi Fred!

   

   (dont hate me)

   Do you think you may be interested in a small project? I want to try and build a piece that you put in/on your rear bumpers to collect energy while stuck in traffic.

  I know it is a stupid waste of money, but since you have the pieces....

 I was thinking, that with individual cells you could easily angle them at every joint; perhaps enough to get a 'concave' structure. This would improve on collecting ablity and remove the cells from the points of contact.

   I think, not entirely sure... that it could power a light in the car... perhaps the dome light or something else. More importantly, it would be interesting to record the energy collected in 1 work week.

                   

[iFred]

Hi Juiced. I'm sorry but at this time I have so many things/project on the go that I just don't have any time to play around at this time. perhaps later on or next year I'll look into it and let you know, don't take it personally, i'm just over worked at this point. Thanks again!

Fred.

[juiced]

Oh i understand!

  I will try it once i have the chance.

[Nando]

Fred:

Your circuits ( both)will blow the transistors (base) because you are not limiting the base current.

You have not indicated the LED current and you may waste a lot of energy in the load resistor.

The scheme for the LED ON when the charging current stops should be done with a very low current and another transistor to control the driver transistor.

Do not use Zener diodes unless you are quite familiar with them, their behavior and their electrical characteristics.

It would be best if you use a photocell to detect darkness to turn the "night

Light" on.

In addition it is best to add some parts to have a PWM current controller for long battery life.

Regards

Nando