2 Watts from an old 2N3055 as a solarcell ?

[prometheus_effect]

Hi Walt,

Try connecting the emitter and collector together. That way you get to use both NP junctions (base to emitter and base to collector) to capture photo electrons.

A 3/4" diameter lens would capture about 0.3w of solar energy. Max solar energy at sea level is about 0.1w/sq cm or 0.65w/sq inch.

To calculate power you need to measure both voltage and current. I suggest you try a 4.7, 2.2, 1, 0.47, 0.22 0.1 ohm resistor as the load and plot what you get. The cell voltage produce be around 0.5 - 0.6 volts until it hits the peak power point then drops quite sharply. The peak power point is just before the cell voltage drops sharply. I have attached a typical PV (photovoltaic) IV curve.

Here in Australia a typical house uses around 5,000 to 6,000 kWh annually. Do you know your annual kWh usage?

The company I work for is developing a very innovative solar concentrator and tracking system which should deliver annual kWhs at about 1/2 the cost of traditional fixed flat panels. It is designed to be mounted on domestic roof tops and can even be mounted on north facing roofs to avoid loss of street scape if the home faces south. Reverse the directions for the southern side of the planet.

BTW optical grade acrylic can handle the heat load as it transmits 93% of the light passsing through. Generally glass has higher losses, is much more fragile and weighs more than optical grade acrylic.

Greg

[prometheus_effect]

Guys,

Here are three more examples I found. Note the very much larger die size for the MJ21193 (middle) verus the 2N3055 (left). This transistor (the MJ21193) should really generate some hefty amps.

Greg

[Walter Hofmann]

Hi Walt,

Try connecting the emitter and collector together. That way you get to use both NP junctions (base to emitter and base to collector) to capture photo electrons.

A 3/4" diameter lens would capture about 0.3w of solar energy. Max solar energy at sea level is about 0.1w/sq cm or 0.65w/sq inch.

To calculate power you need to measure both voltage and current. I suggest you try a 4.7, 2.2, 1, 0.47, 0.22 0.1 ohm resistor as the load and plot what you get. The cell voltage produce be around 0.5 - 0.6 volts until it hits the peak power point then drops quite sharply. The peak power point is just before the cell voltage drops sharply. I have attached a typical PV (photovoltaic) IV curve.

Here in Australia a typical house uses around 5,000 to 6,000 kWh annually. Do you know your annual kWh usage?

The company I work for is developing a very innovative solar concentrator and tracking system which should deliver annual kWhs at about 1/2 the cost of traditional fixed flat panels. It is designed to be mounted on domestic roof tops and can even be mounted on north facing roofs to avoid loss of street scape if the home faces south. Reverse the directions for the southern side of the planet.

BTW optical grade acrylic can handle the heat load as it transmits 93% of the light passsing through. Generally glass has higher losses, is much more fragile and weighs more than optical grade acrylic.

Greg

Hi greg,
it was a typo my house needs 15 to 18.000Kw.
You know I am not realy in to the solar scene, because here we got great sun times but there are many month 4month rainy season, 5month hurricane season) where as I have testet there is not enough to run solar cells this test was just for fun and the mentioned currentoutput. Maybe later I will do some more testing.
greetings
walt

[2tiger]

Hi
I?m new in this Forum, and my english is not very good, but I will try my best.

Well I bought 3   2n3055, cut off the tops and connected them in series.
On a sunny day I get 1,47 V and on a very cloudy day 0,82 V out, without magnifying glas.
Then I connected a little motor from an old walkmann to a simple Battery (1,5 V) to messure the current (0,355 A).

So I thought that it woud be no problem for the "transistor-solarcell" to drive the motor....

...but nothing happens!!! 
The voltage breaked down and the Ampmeter displayed 0,005 A.

Is that right?
That the high Amps are only produced by concentrating the light with a magnifying glas?
In that case I will try to get some and try out again.

[hartiberlin]

Yes,please try with a magnifiying glas and report again.
Thanks !