version H28986 2014
H28986
Joulemeter and Wattmeter
NFU 381
The Joulemeter and Wattmeter, is intended for measuring energy used (in joules and kilojoules)
and power (in watts) for a wide range of electrical and electronic devices, and is designed to
replace the previous model whilst improving the performance and being easier to use.
Technical Information
Check the operating voltage rating label on the instrument
Mains input 240V 50Hz,Instrument fuse T100mA Mains plug 5A recommended.
Input characteristics
Input range for linear operation
0 to ±24V peak, d.c. or a.c. (sine wave 0 to 17V RMS)
Frequency range
d.c. to 10kHz
Input resistance without load
125kΩ
Output characteristics
Output resistance on lowest range = 1kΩ
Output resistance on highest range = 10mΩ plus wiring resistance
No load current with supply p.d. = 10V 10/1.25 x 105 A = 80µA
Maximum ratings on each range
The maximum thermal ratings of the shunts are represented by the following current maxima:
low
200µA
2mA
20mA
200mA
2A
high
10A
