User Manual

7.4. Logic Frequency/Duty Ratio Measurement
The frequency range is of 5Hz ~ 2MHz（Vp 2.5 ~ 5V), while the duty ratio measurement range being
of 10% ~ 90%. And the measurement methods are as follows:
1. Turn on the power switch and press button.
2. Insert the red testing line into the V/Ω/Hz end and the black testing line into the COM end.
3. Connect the red testing line to high logic level, the black one to low logic level.
4. Read the measured value from the display screen. If the frequency of the measured signal is
lower or higher than the meter’s measurement range, the reading will be displayed as zero. If
the amplitude of signal is too low or the low level is larger than 1 volt, the reading will also
displayed as zero.
5. This measurement is of automatic range, it is null to press the RANGE key.
6. By pressing SELECT key, the meter measures Duty Ratio and display it on the second display
zone. Press SELECT key again to stop Duty Ratio display
7.5. Checking Diodes
This function lets you check diodes and other semiconductors for opens and shorts. It also lets you
determine the forward voltage for diodes. You can use this function, when you need to match diode.
Follow these steps to measure the frequency of a signal:
1. Press FUNC-Switch .
2. Plug the black test lead into the COM-terminal and the red test lead into the V/Ω-terminal.
3. Connect the test lead to the diode to be checked and read the display.
Notes:
* If you check a diode´s forward voltage, you will measure voltage of approx. 1,25 V (Germanium)
or 0,7 V (Silicon) if the diode is not defective.
* If "OL" is displayed, it means the diode is open or above 2,0 V forward voltage. However, if the
display shows a value between 0 V and approx. 2.0 V, it means a forward drop voltage.
* The instrument supplies enough forward voltage to light most LED´s. However, if the LED´s
forward voltage is greater than 2.0 volts, the instrument incorrectly indicates, that the device is
open.
7.6. Checking Continuity
Continuity testing verifies that circuit connections are intact.
Warning!
Never perform a continuity checking on a circuit, that has power connected.
Follow these steps to perform audible continuity test:
1. Press FUNC-Switch Ω (((
°
)))
-34-