Analog and 3-1/2 digital display for +/- 199.9mV
This Circuit is a DPM or digital panel meter.
It has a analog bar graph display and a 3-1/2 digit
digital display. ICL7107 is used in the 200mV
U4A opamp LF353 amplifies the 200mV Full scale input
to the level required for the LM3914 display
circuit. D13-D14 are clamping protection diodes.
Adjust P1 trimpot for a reading of 1000 counts when
a 100.0 mV signal is fed at Vin. Adjust R8 trimpot
to get the 5th led to just turn on at 100mV
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3-1/2 digital display for +/- 199.9mV - del20009
A combination of digital and analog display is
helpful for quick decision making. Analog indicates
even from a distance the process dimension.
Human Brain understands analog better. The digital
is required to note down and record values for
determining a setpoint or performance of a system.
Sometimes a analog recorder with a ink-pen plot
against time is a very good way of process analysis.
Many systems are better studied using graphs not
tables and lists of numbers. A Computer based
data-logger gives greater power to this methods. You
can measure and plot graphs of various types and at
different points and for much longer periods