Teledyne 238 - Thermal conductivity analyzer - Manual (Page 7)

1-3 Teledyne Analytical Instruments
Thermal Conductivity Analyzer Introduction 1
All electrical interconnections are made to the terminal strips on the
mother board; this board also contains an unusual feature — a series of
regularly-spaced holes in a rectangular pattern, known as a “kludge” space,
is set aside for the installation of circuitry for special customer requirements.
1.2 Plug-in Circuit Boards
Several options are available as convenient plug-in circuit boards;
although these may not all be present in the specific instrument under
consideration, a brief description of some of the more common ones is
offered below, and noted as (optional); PC boards which are not noted as
(optional) are standard features.
1.2.1 T.C. Cell Power Supply/Amplifier Board
This circuit contains an IC regulator that holds the voltage through the
cell to 4.5 V. It also contains a 2-stage IC amplifier, with range resistors.
1.2.2 Differential Power Supply Board
15 Volts, regulated (for electronic amplifiers, etc.), and +24 volts, non-
regulated (for alarm and relay circuitry and certain other functional uses) are
supplied by this circuit.
1.2.3 Alarm Comparator Board (optional)
The comparator alarm circuit is available in single or dual configura-
tions, which can be supplied as high or low alarms, energized above or
below setpoint; adjustment of each alarm setpoint is made using a potenti-
ometer provided on the instrument’s front panel. Power failure or “fail-safe”
alarming can also be provided. Refer to the specifications covering one
individual analyzer for details regarding specific alarm or other optional
provisions.