Diode Test; Frequency Measurement - Conrad M-4660M Bedienungsanleitung

5.6 Diode Test

To test diodes proceed as follows:
1. Connect the lack test lead with the COM-socket (11) and the red test-
lead with the V/Ω-socket (12).
2. Set the measuring function switch to "
lead tips with the object under measurement to an off-circuit semi-
conductor line, the RED probe-tip to the anode, the BLACK test-lead
tip to the cathode (as a rule it is marked with a coloured ring, point
etc.)
If you check a diode's forward voltage, you will measure voltage of
approx. 0.25 V (Germanium) or 0.7 V (Silicium) to 2.5 (or 250 mV, 700 mV
to 2500 mV), if the diode is not defective. The middle sub-display will
show 9ood for "good".
If you reverse the probe-tips, this means red to the cathode and black
to the anode, you check the so called reverse direction.
If "OL" is displayed and "Open" in the middle sub-display, the diode
is good. However, if any voltage is displayed, you connected the
object wrong or the diode is defective.
Attention!
During diode test, observe that the diode or the circuit in which it is
built in, must be without voltage. All existing capacities must be
discharged.
Fig. 3 Diode test, (page 141)

5.7 Frequency Measurement

Follow these steps to measure frequency:
1. Connect the black test-lead with the COM-socket (11) and the red
test-lead with the V/Ω socket (12).
2. Set the rotary function switch (7) to "FREQ" and connect the test-lead
tips with the frequency source (generator, etc.).
24
". Now connect the test-
/
Attention!
Observe the max. input limits. Never connect voltages over 50 VDC/
VACrms (rms = eff). It is life dangerous to touch the terminals or probe
tips when measuring voltages over 25 VAC or 35 VDC.
Disconnect the test-leads from the contact points before changing the
meter function and range. The sensitive electronic of the measuring unit
might be destroyed and you expose yourself to severe shock hazard.
If there are voltages below 50 mVrms (at 1 Khz) no frequency measure-
ment is possible.
During frequency measurement, the level of AC voltage is shown on the
small central display in V. In the right-hand small display, the dB value
for the AC voltage is shown.
Fig.5 Frequency measurement, (Page 142)
5.8 Transistor Test
Attention!
The transistor jack is not protected against overload.
To measure the hFe-parameter (of amplification) of a transistor follow
these steps:
1. Set the rotary function switch to hFE position.
2. Insert the transistor you want to measure into the appropriate transi-
stor socket.
Pay attention to the following points:
Hints
• observe the sequence of connection of the transistor (e.g. C-B-E) (you
will find it in the transistor comparative table).
25