7
POTENTIOMETERS
A potentiometer, or pot, is a variable
resistor. This means as the knob
shaft is rotated, the DC resistance
will change. There are three lugs
or soldering terminals on a
conventional potentiometer.
The outside two are the ends
of the resistive strip, and the
center lug is connected to
the wiper. The wiper allows you
to vary the DC resistance relative
to its position along the resistive
strip, or relative to the
outer two lugs.
Potentiometers come in
two varieties, linear taper
and audio taper. The linear
taper pot’s taper works at a 1:1
ratio. Audio taper has a special
logarithmic ratio.
Audio taper is used because our ears don’t hear
changes in volume in a linear fashion as you might
expect. As the volume increases, a greater change
in signal or sound pressure is required to perceive a
smooth transition.
LEDs
LED stands for Light Emitting Diode,
and functionally LEDs are very similar to
regular diodes. LEDs are most often used
as indicator lights in pedals. They are
polarized just like diodes and electrolytic
capacitors and must be installed in the
correct orientation to work. The positive
(anode) lead of the LED will be longer and
the anode side of the LED housing will be
round. The negative (cathode) lead of the
LED will be shorter and the cathode side
of the LED housing will be flat. LEDs are
mounted inside of a bezel, which protects
the LED and insulates the leads from
shorting against the enclosure or any
internal components.
2N5089
TRANSISTORS
Transistors are used to amplify electrical signals.
They have a flat side and a round side. The location
on the printed circuit board also has a flat side
and a round side. Match the orientation of the
component to this outline.
UNDERSTANDING ELECTRONIC
COMPONENTS
