Solar Cells + Volatge
Solar Cells + Volatge
(OP)
How can I increase the voltage output on a solar cell from .5V to 1.5+V ? I would like to do this without adding additional cells. Is there a way to do this with a transistor charging the primary coil of a transformer? If so, any idea what type of transistor would work? I would like the profile to be as small as possible. I am trying to power a diode straight from the cell, no battery.





RE: Solar Cells + Volatge
RE: Solar Cells + Volatge
If you truly mean diode and not LED, then there are diodes that work down to 0.2Volts. Check the better shottkey diodes.
RE: Solar Cells + Volatge
If you are just using the solar cell as a light intesity detector, then you can use a simple voltage translator circuit. The can be accomplished with op-amps.
Good Luck and keep us posted!
RE: Solar Cells + Volatge
Yes, this is an L.E.D (red so far, lowest voltage I found), and I was not aware of the lower .2 V on the market. I thought for the whole npn deal to work, each L.E.D is within a fixed range of voltage, therefore determining the color of light. I’ll look around for a source for the shottkey diodes– THANKS
I researched the op-amp idea some time ago. The circuits I reviewed relied on a 9V battery to power the op-amp (logic) itself, and I would like to use a solar cell only. Any further input on this would be appreciated.
Thanks again!
RE: Solar Cells + Volatge
About the only other thing you can try is to add a DC to DC converter to the solar cell output. I am not sure how low the input voltage can be, but maybe you can take a look on the web. However, if you are going to get that involved, then maybe it might be easier to simply add another solar cell?
Good luck and keep us posted!
RE: Solar Cells + Volatge
RE: Solar Cells + Volatge
RE: Solar Cells + Volatge
The lowest input DC-DC converter I have seen takes a 1.5Volt input.
See app. notes at http://www.linear-tech.com/
I think are stuck with adding more cells. If you are only trying light an LED, you might find some cheap hobbyist cells which have only 50mA or so of current output.
RE: Solar Cells + Volatge
RE: Solar Cells + Volatge
even with more light the voltage of one solar cell will not rise significantly, have a look in a datasheet. More light will increase the short circuit current available from the cell.
RE: Solar Cells + Volatge
RE: Solar Cells + Volatge
RE: Solar Cells + Volatge
Thanks for the continued feedback!
RE: Solar Cells + Volatge
If you realy want to solve the problem with voltage conversion try to find of germanium transistor and built an self-oscillating flyback converter with it. This should be possible since a germanium junction needs only 0,2..0,3 V to operate.
RE: Solar Cells + Volatge
Maybe a tunnel-diode oscilator would be appropriate for that, as it normally works only at small voltage supplies? Search the web for "tunnel diode oscillator".
RE: Solar Cells + Volatge
RE: Solar Cells + Volatge
RE: Solar Cells + Volatge
Good luck!
Jarvis
RE: Solar Cells + Volatge
can use electromechanical chopper/xformer
OR
Use MOSFET's to chop low VTG into XFORMER.
Drive their gates with CMOS OSC. running from
e.g. 6V battery. Recharge this from XFORMER
secondary.
<nbucska@pcperipherals.com>