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You turn a knob or slide a lever, them together to solve complex
and all the lights dim. problems.
Remember, things that are We’re not going to go into the
connected to the outlets or wall details of how to design transistor
switches in your house run on 120 circuits, but rather, understand
volts if you live in the U.S. (or 220 that they are commonly used as
volts in many other countries). So, either amplifiers or switches. Once
you’re controlling 120 volts (or 240 you start building some
volts) by turning a single small experiments and looking at their
knob. Now, imagine that instead schematic diagrams, you’ll get a
of you turning that knob, you wired better idea of how they are used.
up a motor (like you did in the Transistors come in all sizes, and
Electricity unit) to a 3 volt battery some things that look like
pack, and attached the motor to transistors really aren't transistors
the dimmer knob so the motor at all! The ones we are going to
would turn it. This way, you could use have three leads and tiny
make a motor running on 3 volts writing on the flat side (like the
control a 120 volt light. This is one shown here). Each lead has a
basically what a transistor does. It specific name and job - and we're
takes a small voltage (or current) going to use two transistors (the
and uses it to control a larger one. NPN and PNP) that look alike, but
Transistors are commonly used in the wiring is different. The three
amplifiers (think stereo or iPod), wires on the transistors each have
they are also used as switches their own name: an emitter (E) ,
(The computer you’re reading this base (B), and collector (C). We'll
on probably has millions of go over in the video which wire
transistors in it). They are used in lead does which job.
amplifiers to make voltages higher, Okay, so now you know that
which translates to louder sounds transistors are like a valve in your
when we run it to a speaker. circuit - they allow electricity to
When they are used as switches, flow up one lead and down the
we can have one switch control other when the valve is open.
another, or even dozens of other When the valve is closed, there's
ones, each performing a different no flow of electricity. Transistors
function, or maybe going to long are also one of the most sensitive
chains of even more transistor components we're going to be
switches. We can even link lots of using. If you solder them too
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