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IDENTIFYING UNKNOWN COMPONENTS
Occasionally you may encounter small value inductors
and axial lead ceramic capacitors which look like the
more common axial lead film resistor. If these
components get mixed up in your parts bin, you may
have difficulty identifying the component. This may also
be a concern with chip capacitors, chip inductors, and a
few other axial lead inductors and capacitors on which
the markings are difficult to interpret or are not visible.
Fig. 28: Use this flow chart to help identify small
axial lead inductors, capacitors, and resistors from
one another.
You can use the LC103 tests to sort these component
types from each other. Figure 28 shows, in flow chart
form, the procedure you need to follow. Before
beginning the test, zero the test leads. You begin
identifying the component with a capacitor value test.
Depending on the reading, you either use the leakage test
or inductor value test to further isolate the component.
Finally, if the component appears to be an inductor, you
use the ringing test as confirmation.
———————— WARNING —————————
Do not apply more than 10 volts across an unknown
capacitor, resistor, or inductor. Most chip, “film”
package, and axial lead inductors and capacitors will
have voltage ratings greater than 10 volts. If in doubt
about an unknown component’s voltage rating, use
another method to identify it, if possible, or use a
lower test voltage.
———————— ATTENTION ————————
Ne pas appliquer plus de 10 volts sur une capacité,
une résistance ou une bobine de valeur inconnue. La
plupart supérieur a 10V. Si vous avez des doutes sur
le voltage du composant utiliser une autre méthode
pour l’identifier, si c’est possible, ou utiliser le test
avec un voltage bas.
NOTE: This test is only intended to help you sort
inductors, capacitors and resistors in “film resistor”
type, chip type or small axial lead packages which are
difficult to identify by physical appearance or any other
means.
CAPACITOR TESTING
Capacitance Measurement Accuracy
The LC103 measures the capacitor charge time as the
capacitor is charged with a constant current. This gives
the most accurate measurement of true capacity
available. Capacity values measured with the ReZolver
may or may not exactly match readings on other
instruments which use a different measuring technique.
Bridges, for example, measure capacitive reactance
using an AC signal. Capacitive reactance changes with
frequency. Therefore, two bridges operating at different
frequencies will give different capacity readings.
Electrolytic capacitors may normally read up to slightly
higher than their marked value when measured with the
LC103. This is because electrolytics are marked
according to their value as measured on an AC-type
impedance bridge. The value of an electrolytic changes
greatly with the measurement frequency. In addition,
electrolytics most commonly fail due to leakage,
dielectric absorption, or ESR. When an electrolytic does
change value, the value drops far below the marked
value.
Measuring Small Capacitance Values In Noisy
Environments
The sensitive ReZolver measuring circuits may be
affected by large, outside signals (such as the AC fields
radiated by some lights and power transformers) when
small capacitance values are being measured. Special
circuits in the LC103 help minimize noise pickup and
stabilize the readings.
Measurements of small value capacitors in noisy
environments may be further improved by grounding the
LC103 case to earth ground.
Connect Unknown Capacitor Inductor or Resistor
Measure C Value
Component may be
resistor or small capacitor
Component is capacitor
Reading is Value
Reading opf,
"0000" or error>
< 200 pf
> QuA
Component is
resistor
QuA
> 200 pf
Measure
leakage at 10V
Component may be
resistor or
very low Q coil
Component is
inductor
Component is
small value resistor
Component is capacitor
or resistor > 100m ohm
Component may be
large resistor
< 10 > 10
Inductor Ringer Test
< 0 > 0 "Open"
Measure L Value
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