CHAPTER 11 ■ POWER ON!
Circuit Summary
Important things described in this chapter:
- A schematic is a symbolic illustration of the parts in a circuit.
- Each part in a schematic is labeled with a letter and number so that it can be referred
to without confusing it with any other part in that particular schematic. - You can test voltage at any point by connecting the black test probe to the negative
end of the battery and touching the red test probe to the point to be measured. - You can test voltage used by (dropped across) a particular part by connecting the red
test probe immediately before and the black test probe immediately after the part to
be measured. - You can test the current used by an entire circuit by changing the multimeter mode,
switching the red test lead terminal, and connecting the test probes in line with the
positive terminal of the battery. - Battery life is directly proportional to the amount of current a circuit uses.
- The amount of current that passes through it controls the brightness of an LED.
- You can adjust current by changing resistor values.
- Too much current can destroy an LED, so always use a resistor to protect it.
Alligator clips work satisfactorily for short, simple circuits that contain only a few parts. However,
sometimes clips slip off and sometimes the exposed pieces of metal accidentally touch each other.
Sometimes the circuit even becomes a giant tangled ball.
There is a much better way to quickly create test circuits. Read on!