Introduction
Figure 2-1: Flame Ionization Cell
The electrode section of the cell may be removed for inspection by turning off the power, disconnecting the electrode lead plug, and removing the screws, which retain the electrode assembly in the sensor body.
2.3.1 Electrometer-Amplifier
The collector cable is coupled directly to a coaxial fitting located on the electrometer-amplifier PC board. The PC board is located on the side panel next to but outside of the isothermal chamber. See Figure 2-1 and consists of an electrometer amplifier and an operational amplifier. This circuit is a very high-gain, current-to-voltage converter circuit, having an input impedance measuring in the billions of ohms. It is static sensitive and highly susceptible to contamination. Special care must be taken in handling this PC board.
2.3.2 Anode Power Supply
The high voltage anode power supply components are mounted on the anode power supply printed circuit board. High voltage regulation is achieved through the use of series-connected zener diodes. The simplicity of this circuit’s design can be attributed to the extremely low current demand of the anode circuit. The positive output voltage is
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