Tab Electronics Guide to Understanding Electricity ... - Sciences Club

102 Chapter Three
will have two independently adjustable, voltage-regulated outputs; one
positive, and one negative. The adjustment range for each will be from
about 4 to 15 volts. It will be short-circuit protected (so you can make a
“goof” without destroying part of the supply), and it will go into currentlimit
mode at about 1.5 amps. The current limit feature allows the power
supply to double as a battery charger (with certain precautions). A handy
feature will be two additional fuse protected “raw” DC outputs ( and
34 volts) for testing audio amplifiers, or powering higher voltage projects.
In short, you will discover it to be a versatile and valuable piece of test
equipment.
Materials Needed for Completion of This
Section
Throughout the remainder of this book, I will always assume that you
have a DVM (or equivalent), soldering tools, alligator clip leads, hook-up
wire, mounting hardware, and the necessary hand tools. The materials
list for each project will only list the materials and components actually
used in the project itself.
Quantity
Item Description
1 9 9 3 (w d h)-inch (or larger) metal
project box
1 Grounded (3-conductor) power cord
1 Power-cord strain relief
1 SPST 10-amp on-off switch
2 24-volt at 2-amp transformers (120-volt
primary)
1 3AG size ( 1 4
1 1 4
-inch) fuse block or fuse
holder
1 2-amp 250-volt slow-blow fuse
1 Locking terminal solder lug (see text)
The project box doesn’t have to be fancy and expensive unless you’re
the type that wants to go first class all the way. The enclosure from a
junked CD player or VCR should do nicely, provided you rework the
front panel. (Front panels can be modified to accommodate almost any
need by placing a sheet of chassis aluminum over the face of the original
front panel. This hides the original front panel artwork, covers the