solar cell, this circuit
isn’t going to supply a
lot of current, so you
probably don’t have to
worry about using a
heatsink for the
voltage regulator. The
positive output from
the solar cell is connected to the Vin of
the voltage regulator.
The Vout from the
voltage regulator will
get sent to the anode of
the battery. The ground
(or case) of the voltage regulator is sent
to the cathode of the battery. The four
diodes are wired in series. The ‘ground’ or
negative side of the diodes hook up to
the ground side of the solar cell.
FIGURE 1. Circuit
diagram.
FIGURE 2. Circuit elements
resting on solar panel.
FIGURE 3. Using the
system to trickle
charge a battery.
How the Circuit
Works
If the diodes were removed or
bypassed, the voltage out would be
about 12 volts. A diode is a semiconductor. If the diode was a perfect
semiconductor, it would have
infinite conductivity in one direction,
and infinite resistance in the other.
Alas, the world we live in isn’t perfect, and neither is the diode. Each
diode has a 0.6 volt ‘breakdown’ voltage
that needs to be overcome. So, each
diode adds this 0.6 volt to the potential
of the ground. Since we are raising the
potential, in slang, we are ‘floating’ the
ground — and forcing the output of the
regulator to increase by 2. 4 volts, giving
us the 14. 6 V we need! SV
SERVO 09.2007 45
