Eberline ESP-1 - Page 11

D
'
u
u
The internal controls consist of four potentiometers and four switches accessible through
the door on the right side of the instrument. They are:
a. LV (Low Voltage): Potentiometer
b. DISCR (discriminator): Potentiometer
c. HV (High Voltage): Potentiometer
d. VO (viewing angle): Potentiometer
e. SPKR (speaker): One switch (three positions)
f. MASK: Two SPST switches
g. TEST: Switch
Power Supply
The ESP-1 uses six "С" cell batteries. In the ESP-1, the end-of-life (EOL) voltage per
cell is approximately 0.93 Vdc using carbon-zinc cells. Six carbon-zinc batteries provide
approximately 250 hours of continuous use (excluding display lighting). Operation with
alkaline cells provides even longer battery life. The ESP-1 senses the low battery
condition at approximately 0.95 Vdc/cell and signals the user by blinking the first
character on the display. This indicates that at least 4 hours of operation remain before
the end of battery life. The ESP-1 is programmed to tum itself off after it has operated
for 2 hours under the "low voltage" condition (first character blinking). The instrument
can be tumed on by the operator and will operate for another 2 hours after which it will
turn itself off again.
The ESP-1 computer always has a supply of power to the memory so that data will be
retained when the power switch is off. The typical battery drain with power off is less
than 10 μα; therefore, the batteries should be changed at least once a year. To allow
battery change without loss of memory, the ESP-1 uses a 0.047-F capacitor to supply
power to the computer. This allows about 20 minutes to change batteries.
ESP1.MAN/February 1992
1-3