Tec Control Board; Pmt Preamplifier - Teledyne T101 Operation Manual

Teledyne ML - T101 Operation Manual

10.4.5.2. TEC Control Board

TEC Control Power Status LED
TEC Control Test Points

10.4.6. PMT PREAMPLIFIER

Figure 10-15. PMT Cooling System
The TEC control printed circuit assembly is located on the sensor housing assembly,
under the slanted shroud, next to the cooling fins and directly above the cooling fan.
Using the amplified PMT temperature signal from the PMT preamplifier board (Section
10.4.6); it sets the drive voltage for the thermoelectric cooler. The warmer the PMT gets,
the more current is passed through the TEC causing it to pump more heat to the heat
sink.
A red LED located on the top edge of this assembly glows constantly to indicate that the
control circuit is receiving power.
Four test points are also located at the top of this assembly they are numbered left to
right start with the point immediately to the right of the power status LED. See Section
9.5.3 for more information.
The PMT preamplifier board amplifies the PMT signal into a useable analog voltage
(PMT) that can be processed by the motherboard into a digital signal to be used by the
CPU to calculate the H
2
The output signal of the PMT is controlled by two different adjustments. First, the
voltage across the electron multiplier array of the PMT is adjusted with a set of two
hexadecimal switches. Adjusting this voltage directly affects the HVPS voltage and,
hence, the signal from the PMT. Secondly, the gain of the amplified signal can further
S concentration of the gas in the sample chamber.
Principles Of Operation
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