DS

This circuit will provide an indication whenever the input voltage differs from two defined limits, V1 and V2. The limits are adjustable and the circuit made to trigger from the adjustable "window". Circuit Diagram: Notes: This circuit will provide an indication whenever the input voltage differs from two defined limits, V1 and V2. The supply voltage, Vcc must be higher than the highest input voltage by at least 2 volts. One application here is to monitor a 12V car battery. V1 could be set to 14V and V2 to 11V thus giving an indication of over charge or a weak battery. Please Note. Only pins 7 and 4 (power supply), pin 6 (output) and pins 2 and 3 (inverting and non-inverting inputs) are used. All other pins are not connected. The pinout for the CA3140 is shown below. The op-amps used here are MOSFET CA3140. They are used to advantage as they have very little output offset voltage and can switch down to near 0 volts. If any other op-amp is used such as LF351 or CA741 then it w...

Here’s a digital frequency comparator for oscillators that indicates the result through a 7-segment display and a light-emitting diode (LED). When the frequency count of an oscillator is below ‘8,’ the corresponding LED remains turned off. As soon as the count reaches ‘8,’ the LED turns on and the 7-segment display shows ‘8.’ This demo circuit uses two NE555 timers configured as astable free-running oscillators, whose frequencies are to be compared. The circuit of the digital frequency comparator portion comprises two 74LS90 decade counter ICs (IC2 and IC6), two 74LS47 7-segment display driver ICs (IC3 and IC7), 74LS74 set/reset flip-flop (IC4), 74LS00 NAND gate (IC8) and two 7-segment displays (DIS1 and DIS2). The astable free-running oscillators built around the timers are the frequency sources for the corresponding counters. Digital Frequency Comparator Circuit Diagram When power supply to the circuit is switched on, timing capacitor C1 starts charging through resistor R1 and potmet...

OP AMP COMPARATOR CHARACTERISTICS The important characteristics of an operational amplifier comparator is as follows:- • SPEED OF OPERATION • ACCURACY • COMPATIBILITY OF OUTPUT Read More.....