Voltage Comparator:-
Voltage comparator is a opamp amplifier circuit without a negative feedback. A comparator has two input voltage & one output voltage, because of high open loop voltage gain of an OP-amp (oprational amplifier).
The input voltage V1 and V2. If the differential input is positive the ckt is driven to saturation and output goes maximum +ve voltage. Reverse happens when the differential input goes negative (-ve) that is output is maximum negative. The circuit is called comparator because it compare V1 & V2 to produce a saturated negative or positive voltage or output.
Diode Comparator:-
A simple diode circuit is shown in this figure. The diode remains in forward bias till the input voltage Vin is less than the battery voltage V and output remains constant at V . As soon as Vin accept the diode becomes in reverse bias and output become equal to the input voltage Vin.
Application of voltage comparator :-
- It is used in analogue to digital conversion.
- It is used in conversion of sine wave into a square wave.
- It is used in Pulse time modulation.
Time based generator:-
The generator which is used for generation of linear variable voltage concering time in known as time based generated. These waves are used in CRT for deflection of beam in horizontal direction. The time based generator is also used in radar system for determining the range of the target. The oscilloscope uses the waveform that varies with the time.
The variable resistor are charges the capacitor in the circuit. The capacitor discharges by the transistor Q1. The charge and discharge of the capacitor generate the waveform shown above. The transistor Q1 becomes ON with the help of input voltage Vi . The transistor provides the low resistance through the capacitor becomes discharge.
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