Hioki 3181-01, Instruction Manual

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6
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Chapter 3 Principle of Operation
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Absolute
value
Rms
conversion
Auto-zero
Low-pass
filter
VF
converter
Absolute
value
Rms
conversion
3-1/2 digit
A-D
3-1/2 digit
LCD
6-digit
counter
Decoder
driver
Division
(10
6
)
6-digit
LCD
Clock
oscillator
Division
(60)
Division
(60)
Division
(2
15
)
Timer
9 9
Power output
Voltage output
Current output
To VF converter
V
IN
A
IN
Multiplier
32.768 kHz
1 s pulse 1 min pulse 1 h pulse
Figure 3.1-2 The Block Diagram 2
e = Ecos ω t
i = lcos(
ω
t+
θ
)
P=e ･ i=Elcos θ + Elcos(2 ω t+ θ )
P=Elcos θ
Figure 3.1-3 Power Calculation Waveform
The voltage and current waveforms in Figure 3.1-3 are
described by equations
and .
Sinewave AC voltage e = Ecos ω t [V]
Sinewave AC current i = Icos( ω t + θ ) [A]
The product of e and i representing the voltage-current
product is the instantaneous power.
Instantaneous power p = e
･
i = 2EIcos ω t ･ cos( ω t + θ )
= EIcos(2 ω t + θ ) + EIcos θ
[W]