Page 477 - Instrumentation Reference Book 3E

460 Electrical measurements
c

. Ri
N
3 Multiplier =-
1:N
Ill

- Low-pass
filter

d
i(t) Current to
-
-W pulse-width Averaging + d.c. output
converter a v(t)i(t)
v(r)
(b)

iiL

V,,, ai B

1

j Magnetic
flux B
Hall effect Hall effect wattmeter
(C)

Figure 20.44 (a) Four-quadrant analog multiplier wattmeter; (b) time-division multiplication wattmeter; (c) Hall-effect
wattmeter.