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How many resistors are needed for the comparator circuit?
As above, the voltage divider network provides a set of reference voltages for the individual op-amp comparator circuits. To produce the four reference voltages will require five resistors. The junction at the bottom pair of resistors will produce a reference voltage that is one-fifth the supply voltage, 1/5Vcc using equal value resistors.
How is a voltage comparator connected to a power supply?
Here, the open collector output from the voltage comparator is connected to a voltage source via a single pull-up resistor (and an LED for indication) which pulls the single output high to the power supply. When the output switch is HIGH it creates a high impedance path, therefore no current flows as V OUT = Vcc.
How is the inverting comparator circuit connected to the operational amplifier?
Inverting Comparator Circuit In the inverting configuration, which is the opposite of the positive configuration above, the reference voltage is connected to the non-inverting input of the operational amplifier while the input signal is connected to the inverting input.
What should the reference voltage be for an op-amp comparator?
Comparator Reference Voltages In theory the comparators reference voltage can be set to be anywhere between 0v and the supply voltage but there are practical limitations on the actual voltage range depending on the op-amp comparator being device used. Positive and Negative Voltage Comparators
What does a comparator do in a circuit?
A comparator is a circuit that compares two input voltages or currents and gives output High or Low as per input signal. The Output is a digital form according to the input signal compared with the reference.
What is the purpose of a resistor in a circuit?
Resistors are used to adjust voltage and current to suit for a particular circuit to work. He the dc voltage is fixed say 3,6,9,12,1824 etc. But actual circuit require different voltages. The resistor circuits are used to get different voltages and currents to operate particular circuits.
Can a resistive voltage divider be used as a comparator?
Generally, a resistive voltage divider is used to set the input reference voltage of a comparator, but a battery source, zener diode or potentiometer for a variable reference voltage can all be used as shown.
Why is no feedback used in the comparator?
Because no feedback is used, the input signal is amplified by the full open-loop gain of the op-amp. Even a very small input voltage (less than a millivolt either side of Vth) will be enough to drive the output to either the minimum or maximum output voltage, as shown in the plots of Vin and Vout.
When to use positive feedback around an op-amp comparator?
The use of positive feedback around an op-amp comparator means that once the output is triggered into saturation at either level, there must be a significant change to the input signal VIN before the output switches back to the original saturation point.