DiscoverCircuits.com -- Hobby Corner
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Tuesday, June 01, 2021 03:06 PM
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LINK to Dave's circuit, but DO NOT COPY any files to your WEB
Also see design in
Circuit Solutions section
design a marginal AC to DC linear power supply provides a voltage boost, so it can
maintain regulation at low line voltages.
added components are wired at the AC input and the + DC output of an existing bridge
rectifier circuit. The components act as a full wave “charge pump” which will boost the DC
output voltage across the main filter capacitor C3. Without the boost circuit, when the AC
line voltage drops to 105vac, the DC output voltage only reaches 11.5 volts, too low for a
12v voltage regulator. With the parts added, the output voltage increases by about 2
volts, boosting the voltage to 13.5 volts. This is just enough for many low voltage drop
12 volt regulators. Since a fair amount of current is pumped in and out of the 220uF caps,
they should be the type rated for high ripple current or low
equivalent series resistance (ESR).