Philips PM2519 - Page 23

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2.3.2.2. Alternating voltage measurements
The input voltage to be measured is applied to the AC voltage attenuator, which changes the attenuation
factor by means of RC-networks switched by a FET switch. The table for each range gives the attenuation
factor, the RMS converter input sensitivity and the range signals.
The basic attenuation (10) is given by the voltage division of the components R1400, R1401//C1401, C1402
and R1404. An attenuation of 1000 is achieved by the basic attenuation and the resistors R1403 and R1402,
The attenuation signal is then passed to the RMS converter, which produces a d.c. signal between O and
900 mV. Any d.c. component at the input is blocked by C1400.
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al 2!
VoImA O—_-——— oie |
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1400
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i
cuoz
3p9
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=
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Fig. 2.4. AC attenuator
RANGE
RANGE | ATTENUATION | AC INPUT RANGE Fane F | Ri PM 2519 INPUT AC
RNG F
100 mV 2 MQ
1000 mV 2 MQ
100 mV 1.802 MQ
1000 mV 1,802 MQ