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This automotive electronic project simple but digital pressure gauge circuit. Using an intersil ICL 7106 A/D converter chip and an LED display module, this gauge uses a Sensym Corp. Digital Pressure Gauge Circuit Diagram: Pressure transducer SXlOOpn (100 psi full scale) in a Wheatstone bridge configuration to drive an op amp (ICla, b, c) translator circuit that supplies a dc voltage to IC2 that is proportional to pressure. R6 sets the gain of IC1A (full-scale sensitivity) and R16 supplies a zero adjustment. IC3 provides regulated + 5 V to power the circuit.

This simple dual digital dice is based on three low-cost ICs, a few transistors and a handful of LEDs. IC1a & IC1b operate as an oscillator with a frequency of about 4kHz and this clocks IC2. The frequency of oscillation is not critical - it simply needs to be high enough to prevent cheating. IC2 and IC3 are 4516 binary counters, configured to count in binary from 1-6. A power-on reset is not required here since, if the initial state is outside the correct range, the counters will count into the correct range after a few clock pulses. Let's first consider how IC2 operates. When the counter reaches "7" (ie, 111), the AND gate formed by diodes D1 & D2 and the 47kO resistor applies a high to the PE pin (pin 1). Simple But Low-Cost Dual Digital Dice Circuit Diagram This presets the counter to 1 (ie, 001) and so PE goes low again. The counter then increments in the normal manner until it reaches "7" again. Counter IC3 operates in the same manner except that t...