Drawing Number: 21096
Revision: NR
SERIES 134A20 TOURMALINE PRESSURE BAR GENERAL OPERATION MANUAL
3
Note that the Series 402A In-Line Amplifier
features a frequency response of greater than 1
MHz. A charge amplifier used with the tourmaline
pressure bar may limit the upper frequency
response of the system.
Connecting the Series 134A Tourmaline Pressure
Bar directly to a readout instrument without the use
of the Series 402A In-Line Amplifier or other
impedance-converting device can be done with
some limitations. The input impedance of the
readout instrument may be significantly low to
create a very high-pass filtering effect. This can
affect measurement of pulse duration or amplitude
of a slow-rising pulse. Also, the voltage sensitivity
of the output of the tourmaline bar into the readout
instrument is affected by the cable capacitance and
input capacitance of the readout instrument.
Contact the factory with any questions regarding
use of the sensor in the charge output mode.
6.1
USE OF THE IN-LINE
AMPLIFIER
The Series 402A In-Line Amplifier is used to
convert the high-impedance output of the
tourmaline pressure bar into a low-impedance
output. The in-line amplifier may also be used as a
unity gain amplifier for checking system frequency
response. A signal generator is connected to the
input of the in-line amplifier and fed through the
system.
7.0
MAINTENANCE AND
REPAIR
The electrical connectors on the tourmaline
pressure bar, the input of the in-line amplifier, and
the three-inch, low-noise cable must be kept clean
and dry, especially if they are operating in a dusty
or wet environment. This is to prevent drift due to
low insulation resistance. Also, note the following
precautions:
1. Do not exceed maximum levels.
2. Constant temperatures around the tourmaline bar
should be limited to 150
F. Short-term exposure to
higher temperatures, such as that found in a blast
wave, do not cause damage.
3. Use only PCB power conditioners or approved
alternative.
4. Current to the in-line amplifier must be limited
to not more than 20 mA to avoid damage.
5. If the tourmaline pressure bar and in-line
amplifier are to be left outside overnight or in
humid or rainy environments, they should be coated
with silicone oil and covered.
