Amprobe CR50A Manual De Uso página 7

3. Connect test leads to resistance or circuit to be measured.
4. Read resistance value on Digital Display. Open circuits will be
displayed as an overload condition.
Note: On the 20Ω range, an adjustment potentiometer (ZERO
ADJ.) allows you to zero out the test lead resistance. Short the
test leads and adjust the knob until the display reads zero.
Diode and Transistor Test (Fig -2-)
The diode test measures the voltage drop across the diode junction.
1. Connect the red test lead to the +Rx Input (red) and the black
test lead to the –Rx Input.
2. Set the Function/range switch to � position.
3. Apply probe tip of red lead to the anode and black lead to
the cathode of the diode. The meter's display indicates the
forward voltage drop (approximately 0.7V for silicon diode
or 0.4V for germanium diode). Meter will display overload
condition for an open diode.
4. Reverse test lead connections to the diode to perform a
reverse bias test. Overload indicates a good diode.
Note: Overload condition for both reverse and forward bias tests
indicate an open diode. A low voltage reading for both bias tests
indicates a shorted diode. If the diode is shunted by a resistor of
1000 ohms or less, it must be removed from the circuit before
taking the measurement. Bipolar transistor junctions may be
tested in the same manner described above.
Continuity Test
The Continuity test checks electrical continuity between two
contact points.
1. Set the Function/Range switch to � �.
2. Plug the black test lead into the –Rx jack (black) and connect
the test lead tip to one of the contact points.
3. Plug the red test lead into the +Rx jack (red) and connect its
test lead point to the other contact point. (See Figure 1 for
connections).
4. The internal beeper emits a tone when resistance is less than
approx. 75Ω
Capacitance Measurement (Fig -3-)
Discharge all voltage from the capacitor (via a 100kΩ resistor)
before measuring its value.
3