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Circuits designed by David Johnson, P.E.
Last Updated on:
Thursday, March 22, 2012 06:41 AM
Master Category List
- Dave's Circuits
Text & Graphics
Copyright © David A. Johnson, PE - ALL Rights Reserved.
LINKING to Dave's circuits is permitted but DO NOT COPY to your WEB SITE server! |
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Solar
Circuits |
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Broken Solar
Panels
As illustrated below, one way to salvage a large number of broken solar cells
is to wire them in parallel, not in the more conventional series connection.
Broken cells of various sizes and shapes are grouped together into panels of
about one quarter to one full square foot in area. Those panels are then wired
in series with other similar panels. The result...
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- Solar Insulation
Monitor
An inexpensive PIN photo diode and a 1ma meter movement form a simple sunlight intensity
monitor. The sensor should be placed inside a lightly frosted glass hemisphere to
minimize the influence of the sun’s angle on the sensor. An adjustment resistor
calibrates the meter for a full scale reading under a one sun condition. An
unshielded two conductor cable links the sensor to the meter movement. The sensor
and meter can be separated by up to 200 feet.
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Solar Cell Test
Fixture
If you are considering building your own solar panel, you might try building the solar
cell tester shown below. When constructing a solar panel it is important to make sure
that all the solar cells used in the panel be closely matched for their short circuit
current. One weak cell will lower the efficiency of the whole panel. The system shown
allows individual solar cells to be tested for their short circuit current under a
constant light intensity condition....
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- Solar
Powered Lithium Ion Battery Charger
The circuit below feeds a controlled current and voltage to a 3.6v lithium ion battery.
The current is limited to 300ma and the voltage is limited to 4.2 volts. The circuit
uses a LTC1734 IC from Linear Technology. No diode is needed between the circuit and a 6
volt solar panel....
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- Solar PV cell Test Fixture
This is an illustration of a test fixture, which can be used to test individual solar
cells for short circuit current. Using a PIN photo diode and a control circuit,
the solar cells can be tested under constant light level conditions. A halogen
incandescent lamp is used as the light source. (added 7/06)
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