Technical data

60
ircuit Troubleshooting Strategies
he job of a technician frequently entails "troubleshooting" malfunctioning circuits. Good
oubleshooting skills, although highly demanded in industry, require a thorough understanding of the
asic concepts, and a sense of creativity in applying a solution to correct the problem.
n essential skill to possess is a ready and intuitive understanding of how component faults affect
ircuits in different configurations.
ot every electrical circuit is similar in design. This means every malfunctioning circuit will require a
ifferent method and approach to finding and correcting the problem. This can be very overwhelming
the inexperienced troubleshooter who does not know where to even start. One thing is for certain;
aving a good understanding of the Ohm’s Law relationships and the rules for series and parallel
ircuits is the first step to becoming a top-notch electrical troubleshooter.
fore have the
aximum voltage drop or “source voltage” across it. Any other amount of resistance in the circuit will
e drop. Even resistors with large values in the Mega-ohms cannot
istance.
e full source voltage and the
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b
A
c
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to
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Troubleshooting Series Circuits
Series circuits are usually the simplest type of circuit to troubleshoot because voltmeters can easily be
used to locate voltage drops across specific components in the circuit.
As you learned earlier in this book, there are really only two types of faults in an electrical circuit, opens
and shorts.
When using a voltmeter to check for opens and shorts in a series voltage divider circuit, try to think
about the Ohm’s Law relationship of voltage and resistance. The higher the resistance a component
has, the higher the voltage drop across that component. Consequently, the lower the component
resistance, the lower the voltage drop.
An open in the circuit will essentially be an infinite amount of resistance and will there
m
be irrelevant and will have no voltag
mount of rescompare to an infinite a
In Figure T-1, resistor R
2
has become open. This creates a situation where electrical current is not
owing in the circuit. The voltage drop across the open will be equal to thfl
voltage drop across any other resistance in the circuit will be zero.
Figure T-1