EAI TR-20 Operator's Reference Manual page 26

RESET
HOLD
OPER
4. ATTENUATORS
In the reset mode, the output voltages of the
integrators are set to the values required by
initial conditions of the problem. All other
inputs to the integrator are disconnected.
In the hold mode, the inputs to the integrators
are removed; integration ceases and all vari-
ables are held at the present values.
In the operate mode, the integrators accept
inputs and integration with respect to time
takes place.
One of the simplest and most useful operations performed on an analog computer is
accomplished by using a potentiometer to multiply a voltage by a positive constant
that is less than one. This corresponds to attenuation of the voltage, therefore
potentiometers are often called attenuators. Both terms are used interchangeably
here. Four types of attenuator groups are available for use in the TR-20, All
groups use ten-turn, 5000 ohm potentiometers. The groups are listed below.
GROUP
NO.
OF POTS TYPE OF POT DIAL REMARKS
42.183
2 Carbon
Uncalibrated Does not have Readout
Switches
42.187
2 Carbon
Un c-a
1
i brated Has Readout Switches
42.188
2
Wirewound Calibrated Has Readout Switches
2.1,28
Has Readout Switches
(42.185
&
12.265)
4
Wirewound Calibrated Pots located in Con-
trol Panel area
The Type
42.183,
Type
42.187,
and Type
42.188
Groups have similar patching termina-
tions. The top potentiometer is terminated on the left side of the patching module
and the lower end of this potentiometer is grounded. The lower potentiometer is
terminated on the right side of the patching module and both ends of the potentio-
meter are available for patching. The Type
2.128
Group consists of a patching
module (Type
12.265)
that mounts in the non-linear row of computing components,
and Quad Coefficient Assembly, Type
42.185
that mounts in the control panel area.
The lower end of each potentiometer is grounded. The potentiometers are termina-
ted in order, top to bottom, on the patchirg module.
16