Sect. I Page 1
SECTION I
GENERAL DESCRIPTION
1-1 GENERAL DESCRIPTION The Model 500C Electronic Tachometer Indicator
is similar in circuitry to the 500B except for the
The Model 500B directly measures the frequency meter calibration. The Model 500C is calibrated
of an alternating voltage from 3 cps to 100 KC. in terms of RPM with a counting range from 180
RPM to 6,000,000 RPM. In conjunction with the
It is suitable for laboratory measurement or pro- Hewlett-Packard Model 508B Tachometer Gener-
duction testing of audio and supersonic frequen-
cies or for direct tachometry measurement with ator the 500C will measure speeds from 15 to 40,000
appropriate transducers, such as the -hp- 506A RPM. When used with the Model 506A Optical Tach-
Optical Tachometer Pickup or the -hp- Model
508A/B Tachometer Generators.
The indications of the meter are independent of
input waveform, permitting the instrument to count
. -. sine-waves, square waves, or pulses and to indicate
the average frequency of random events. A RE-
CORDER jack permits operationof a 1 ma recorder,
such as the Esterline-Angus Automatic Recorder,
for continuous frequency record. The impedance
characteristics of this terminal may be adjusted
to match any 1400 ohm (*lo0 ohm) 1 ma recorder
to the 500B meter circuit. The RECORDER jack
also may be employed to drive a remote indicating
meter available from the Hewlett-Packard Company
as an accessory.
I I5 V OPERATION
Besides indicating an applied frequency and pro-
viding a recorder output, however, the Model 500B
is designed to be valuable in two other types of
measurements. First, it is designed to be able to
expand its scale readings by factors of 3 or 10
times, an arrangement that facilitates measure-
ments of frequency changes such as might be
caused by line voltage changes on frequency-gen-
erating circuits. Second, the instrument is de-
signed to provide an output voltage which is
proportional to the applied frequency .This signal
from the PULSE terminal enables the instrument
to be used as a wide band discriminator inap-
plications where the measured signal contains very Y
rapid frequency changes or frequency modulation
The discriminator voltage, when filtered, can be 230V OPERATION
used to measure the amount of deviation in the
signal as well as the rate and components of de-
viation.
B Figure 1-1. Jumper Connections. Power
Transformer Primary |
ACEC
