How to Check Basic Electronic Components Using a Multi-Meter
How to Check Basic Electronic Components Using a Multi-Meter
How to Check Basic Electronic Components Using a Multi-Meter
Basic electronic components such as resistors, capacitors,
diodes and transistors are widely used in any electronic devices
and gadgets. Knowing how to conduct a test on this components using
a multimeter would give you an idea on how to trouble shoot and
repair any defective cellphones or electronic equipments at home.
Below are some basic D.I.Y. regarding proper testing of this
components using a multimeter.How to Check Resistors?
Read the indicated code value indicated in Schematic Diagram
then select the Ohm-scale within but not way below the indicated
value. A resistor is good if its resistance is close to the
indicated value.Tolerance should be considered with the ohmmeter
reading. While, no resistance reading at all on the ohmmeter scale
settings means that the resistor is open. A zero resistance reading
on all ohmmeter scale settings means that the resistor is
shorted.
How to Check Capacitors?
In most cases, a capacitor fails due to the deterioration of the
dielectric material between its plate.Defective capacitors can have
an internal shorted terminals, excessive leakage and degradation of
capacitance meter. For an electrolytic capacitor (capacitors with
polarity), short the terminal capacitor to discharge it prior to
testing.
To test a capacitor, set the multimeter to Rx10 or Rx1K scale.
Connect the tester negative probe to the capacitor positive
terminal and the positive probe to the negative terminal.
A good indication for electrolytic capacitor shows the meter
needle deflecting towards zero and moves back again to infinite
resistance position. For ceramic, Mylar and other capacitor with a
capacitance with less than 1.0 uF, the meter will not deflect at
all.
A defective indication for an electrolytic capacitor shows that
the meter will rest on zero and remain stationary at a point which
is an indication that the capacitor is shorted.
How to Check Diodes?
Set the multimeter knob to any of the resistance position (x1,
x10, x1K or 10K ohm ).Connect the positive probe to the anode and
the negative probe to the cathode.Then connect the positive probe
to the cathode and thenegative probe to the anode of the diode. A
good indication in the first procedure will show the meter
deflected very little or may not deflect at all.
And in the second procedure, the meter will deflect towards
zero.The actual resistance reading is the forward resistance of the
diode.
A defective indication shows that the meter won't deflect at all
even when the probes are reversed. Or the meter deflects at the
same time or almost the same resistance reading for both steps.
How to Check Transistors:
Bipolar transistors are usually checked out of a circuit by
means of an ohmmeter. When it is desired to check for the
resistance across the transistor emitter and collector, NPN or PNP,
ohmmeter probes may be connected either way. A good transistor will
show above a reading above 1000 ohm.
How to determine if it is NPN or PNP transistor?
To determine the correct terminal of the transistors, set the
range selector to x 1 or 10 ohm.Connect the positive probe to the
emitter and the negative probe to the base of the transistor. Note
the reading interchange the connection of the probes to the leads
of the transistor.
Base your conclusion on the table:
POSITIVE PROBE TO: -----NEGATIVE PROBE TO: -----RESISTANCE
READING-- CONCLUSION: Emitter------- -- Base---------- Less than
150 ohm ------Transistor is NPNBase --------------Emitter
--------Infinity ----------------Transistor is NPN
POSITIVE PROBE TO: NEGATIVE PROBE TO: RESISTANCE READING:
CONCLUSION: -Emitter------------Base ---------Infinity
---------------- Transistor is PNPBase --------------- Emitter ---
- Less than 150 ohm ------- Transistor is PNP
Some defective indications of transistors: Resistance between
any pair of the terminals is less than 10 ohms, means that the
transistor is shorted. Resistance between base and emitter or base
collector for both the forward and reverse application of ohmmeter
probes is infinity (meter needle don't deflect), means that the
transistor is open. Transistors overheats (except power
transistors) during normal operating condition means that the
transistor is shorted.
How to Check an LED ( Light Emitting Diode)
Set the Muti-meter to x1 connect the positive probe to cathode
and the negative probe to anode. The good and working LED will then
light up or glow, a busted LED will not.
How to Check a Coil?
Set the multimeter to X1 a good and working coil have a reading
approximately point to zero ohms, without any reading means the
coil is open or busted.
How to Check a Fuse?
A blown SMD Fuse is not visible to our naked eye, just set the
multi-meter to x1 and put both test probe to both end side of the
fuse. A full reading here to zero or continuity check is full.
without any reading means the fuse is already busted.
How to Check IC chips (Integrated Circuits)?
IC Chips is hard to determine faulty by using only a
multi-meter, some advance equipment like the one that the
manufacturer used during their productions. However; you can
determine a faulty chips by some few experiences when it comes to
troubleshooting, One techniques is that by comparing two same
components from one another. like for example; if one chips is
suspected to be faulty, then by replacing it with a good and
working same chips, you can now determine it if the said chips got
a problem. It is a trial and error method at first; but as long as
your experience and knowledge skills increases, you can determine
it more quickly and accurately.Further, we will tackle this issues
and give you some tips and tricks.