NJU9214
s FUNCTION DESCRIPTION
(1) Measurement function
Each measurement functions shown below is available with the NJU9214.
MEASUREMENT
FUNCTION
DC/AC Voltage
DC/AC Current
DC/AC Current
Resistance (Ω)
Frequency ( f )
Capacitance( C )
Tacho (rpm)
Diode ( )
Continuity( )
ADP
RANGE
400mV to 4000V
4mA to 4000mA
40A
400Ω to 40MΩ
100Hz to 1000kHz
4nF to 400μF
6000rpm to 600Krpm
Auto/Manual
Auto : 4-range / Manual : 5-range
∗1
Auto Manual -2 range/ Manual -4 range ∗2
Fixed
Auto : 6 - range / Manual : 6 - range
Auto : 5 - range
Auto : 6 - range / Manual : 6 - range
Auto : 3 - range
Fixed
Fixed
Fixed
∗3
∗1 400mV range ( AC / DC ) is selected in only manual range.
∗2 4mA-4000mA range has Auto / Manual – 2 range and Manual – 4 range mode, each mode
needs its own application circuit.
∗3 ADP is applied for °C, hfe and other measurement
(1-1) Voltage ( DCV, ACV ) measurements
The divided voltages which are output from each resistance R1 to R5 shown in following table are supplied to
A/D converter.
In the AC measurement, after the dividing voltage, these output voltages are converted to DC Voltages with
the external RMS/DC converter. This DC voltage is supplied into A/D converter.
10MΩ resistor for input terminal may be easy to be affected by noises.
Therefore 10MΩ and peripheral circuits require some protection like shields and so on for stable display.
The resistors for attenuating should be selected with a flat temperature characteristic. Especially, the resistors
( 10MΩ, 10kΩ, 1kΩ ) for 400V, 4000V ranges should be selected carefully. For example, when 4,000V is input,
0.4mA ( 4,000V ÷ 10MΩ ) flow through 10MΩ, and the resistor consumes power of 1.6W ( 4,000V × 0.4mA )
and the temperature of the reference resistor.
After measuring at 400V, 4,000V ranges, sometimes the uncorrect value is shown on the display at 4V, 40V
ranges because the value of resister as the attenuator is changed by the temperature.
RANGE
R1(400mV)
R2(4V)
R3(40V)
R4(400V)
R5(4000V)
DIVISION RATE
1
1MΩ / 10MΩ
100kΩ / 10MΩ
10kΩ / 10MΩ
1kΩ / 10MΩ