Elenco Compact Digital Multimeter - Manual (Page 16)

DIODE CHECK
RANGE RESOLUTION MAX TEST CURRENT MAX OPEN CIRCUIT VOLTAGE
DIODE 1mV 1.4mA 2.8V
TRANSISTOR h
FE
TEST
RANGE TEST RANGE TEST CURRENT TEST VOLTAGE
NPN/PNP 0 - 1000 Ib = 10 μA Vce 3V
CONTINUITY TEST
Audible Indication: Less than 20 Ω approx.
-15-
SPECIFICATIONS
GENERAL
DISPLAY 3 1/2 digit LCD, with polarity
OVERRANGE INDICATION 3 least significant digits blanked.
MAXIMUM VOLTAGE BETWEEN
TERMINALS AND EARTH GROUND CAT II 600V
STORAGE ENVIRONMENT –10 O C to 50 O C.
TEMPERATURE COEFFICIENT (0 O C to 18 O C and 28 O C to 50 O C)
less than 0.1 x applicable accuracy
specification per
O C.
POWER 9V alkaline or carbon zinc battery.
FUSE 200mA/250V
DIMENSIONS 126 x 70 x 24mm.
DC VOLTAGE
RANGE RESOLUTION ACCURACY
200mV 0.1mV +0.5% rdg + 2d
2000mV 1mV +0.5% rdg + 2d
20V 10mV +0.5% rdg + 2d
200V 100mV +0.5% rdg + 2d
600V 1V +0.5% rdg + 2d
MAXIMUM ALLOWABLE INPUT 250V rms for 200mV, 600VDC
or rms AC for other ranges.
INPUT IMPEDANCE 1M Ω.
DC CURRENT
RANGE RESOLUTION ACCURACY
200 μA 0.1 μA +1.8% rdg + 2d
2000 μA 1 μA +1.8% rdg + 2d
20mA 10 μA +1.8% rdg + 2d
200mA 100 μA +2.5% rdg + 2d
10A 10mA +3% rdg + 3d
OVERLOAD PROTECTION 200mA/250V fuse ( μA,mA input only).
10A not fused (15 seconds only)
AC VOLTAGE
RANGE RESOLUTION ACCURACY
200V 100mV +2% rdg + 10d
600V 1V +2% rdg + 10d
MAXIMUM ALLOWABLE INPUT 600VDC or rms AC.
FREQUENCY 45 - 450Hz.
RESISTANCE
RANGE RESOLUTION ACCURACY
200 Ω 0.1 Ω +1% rdg + 10d
2000 Ω 1 Ω +1% rdg + 10d
20k Ω 10 Ω +1% rdg + 10d
200k Ω 100 Ω +1% rdg + 10d
2000k Ω 1k Ω +1% rdg + 4d
MAXIMUM OPEN CIRCUIT VOLTAGE 3.2V.
MAXIMUM ALLOWABLE INPUT 250V rms AC
h
FE
MEASUREMENT
Figure 9 shows a simplified diagram of the h
FE
measurement function. Internal circuits in the
7106 IC maintain the COMMON line at 2.8 volts
below V+. When a PNP transistor is plugged into
the transistor socket, base to emitter current
flows through resistor R1. The voltage drop in
resistor R1 due to the collector current is fed to
the 7106 and indicates the h
FE
of the transistor.
For an NPN transistor, the emitter current
through R2 indicates the h
FE
of the transistor.
Figure 9
R1
Common
R3
R2
PNP NPN
7106
100mV
Ref.
Low Pass
Filter
V+
E C
C E
B B
CONTINUITY MEASUREMENT
Figure 8 shows a diagram of the continuity
measurement function. The circuit uses two op-
amps and a piezoelectric buzzer. When the
leads are connected across a circuit and the
resistance less than 20
Ω the circuit oscillates
and the buzzer sounds.
Figure 8