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PWRSUP.CHP
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1990-05-26
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█▀███▀██▀▀▀▀▀██▀▀▀▀▀█
█ ███ ██ ███ ██ █ █ █
█ ▀▀▀ ██ ▀▀▀ ██ █ █ █
█ ███ ██ ███ ██ ███ █ POWER SUPPLIES
▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
│ ┌──┐ ┌───┐
├──┐ │ │ ├──┐ ├───┘
│ │ └──┘ │ │ └───┘
└──┘ └
Examine the schematic drawings listed below. Then, we will
discuss each type in detail as HAM BONE proceeds through
this chapter.
In all schematics, the following component references
are as follows:
* d1 to d4 - 2A 1000 PIV rectifiers (diodes)
* Filter Capacitors - 3300 MF @ 25 VDC
Power Supply #1 of 3
▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
█ █
█ HALF WAVE Power █
█ POWER SUPPLY d1 Transformer █
█ ┌──────────┬────────┤─────────────────┼ ▌▐ ┼───────────┐ █
█ │ │ ┼ ▌▐ ┼ █
█ + │ 12 VAC ┼ ▌▐ ┼ 117 VAC │ █
█ │ ▄▄▄ ┼ ▌▐ ┼ │ █
█ │ Filter ▄▄▄ ┌───÷─────÷────────────┼ ▌▐ ┼─────┐ █
█ │ Cap - │ │ │ █
█ │ ┌────┴────┘ --│--- │ │ █
█ │ Insert d2 for full wave └─ 117VAC█
█ │ │ └─────── ─────█
█ │ │ █
█ └───────────────────────────────────────────────── ─ 12 VDC█
█ └─────────────────────────────────────────────────────── + ──────█
█▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄█
Power Supply #2 of 3 - Note Center-Tapped Transformer
▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
█ FULL-WAVE Center Tapped █
█ BI-POLAR Power █
█ POWER SUPPLY d1 Transformer █
█ ┌──────────┬────────┤─────────────────┼ ▌▐ ┼──────────┐ █
█ │ │ ┼ ▌▐ ┼ └ █
█ + │ 24 VAC ┌──────┤ ▌▐ ┼ 117 VAC █
█ │ ▄▄▄ │ ┼ ▌▐ ┼ ┌ █
█ │ Filter ▄▄▄ ┌───│─────────────────┼ ▌▐ ┼──────────┘ █
█ │ Cap - │ │ d2 │ █
█ │ ┌────│────┘ │ █
█ │ └────────────────────┤ █
█ │ │ - + note polarity│ █
█ │ ├──────█ █────────────────┴──────────────────────■ Com █
█ └────────────────────────────────────────────────■ ─ 12 VDC█
█ └──────────────────────────────────────────────────────■ + 12 VDC█
█▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄█
Power Supply #3 of 3 - Efficient method of getting clean DC
▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
█ █
█ FULL WAVE BRIDGE Power █
█ POWER SUPPLY d1 Transformer █
█ ┌──┤───────┬─────────┼ ▌▐ ┼───────────┐ █
█ ┌──────────┬─────┤ d2 │ ┼ ▌▐ ┼ █
█ + │ └──┤───┐ │ 12 VAC ┼ ▌▐ ┼ 117 VAC │ █
█ │ ▄▄▄ │ └┐ ┼ ▌▐ ┼ │ █
█ │ Filter ▄▄▄ ├─────────────┼ ▌▐ ┼─────┐ █
█ │ Cap - │ ┌──├───┘ ┌┘ │ █
█ │ ┌────┴─────┤ d3 │ │ │ █
█ │ └──├───────┘ └─ 117 VA█
█ │ │ d4 └─────── ─────█
█ │ │ █
█ └───────────────────────────────────────────────── ─ 12 VDC█
█ └─────────────────────────────────────────────────────── + ──────█
█▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄█
As you can see, there are a lot of similarities between the
3 examples. But, there are very important differences in
each of them. It all has to do with the way electrons are
directed (the actual direction of flow) in the device that
you build.
Some electronic devices that operate on DC current handle a
very IMPURE form of DIRECT CURRENT (dc) yet others require
extremely stable and clean DC supply voltages. Therefore,
we can design a power supply that meets our requirements.
Simple is cheap. But, simple may not work.
An LED, for example will glow and a toy motor will run on
"not so clean" DC. However, a computer must have a very
stable and precisely filtered supply of DC, either from a
battery, or a fully regulated power supply. If it doesn't,
IC Chips start going haywire and things, you don't want to
think about, can happen.
Before we get into how the electrons flow through the
diodes and filters, let's see how a power supply might do
us some good. Suppose that you got an old CB radio at a
garage sale for $2.00 and wanted to hook it up on your work
bench to play with. Instead of running a wire from your car
battery to your bench, why not build a $5.00 power supply
that you can use to power many auto radios, ham radios and
even small TVs.
Integrated circuits (linear IC's) have been designed to
provide for very stable DC voltage regulation. If you are
going to be powering devices that require precision voltage
and current regulation, then simply insert one or more of
these "chips" into the DC output of the BRIDGE diode
schematic.
The example schematic #3 - FULL WAVE BRIDGE power supply
comes very close to providing everything you need to build
your new testbench workhorse. And, you can build your own
for about 1/3 of what an off-the-shelf unit would cost. It
might not be as pretty, but you can make it yourself.
Press ESCape to return to the menu...