Schmitt trigger using Op-Amp 741 IC
Engineering | Diploma Linear Integrated Circuits Lab
Aim: To design and setup a Schmitt trigger, plot the input output waveforms and measure
VUT and VLT.
Equipments/Components:
Sl .No Name and Specification Quantity required
1 Dual power supply +/- 15V 1
2 Function generator(0- 1MHz) 1
3 Oscilloscope 1
4 Bread board 1
5 IC 741C 1
6 Resistor 3
7 Probes and connecting wires As required.
Principle:
It is a regenerative comparator or it is a comparator with hysteresis. This circuit uses
positive feedback and the op-amp is operated in saturation. The output can take two values
+Vsat and -Vsat. When output = +Vsat, the voltage appearing at the non-inverting
terminal is VUT or UTP = +Vsat( R1/R1+R2) called the upper threshold point. Similarly
When output = - Vsat, the voltage appearing at the non-inverting terminal is VLT or
LTP = -Vsat( R1/R1+R2) called the lower threshold point. When Vin is greater than UTP, the
output will switch from +Vsat to -Vsat. Similarly When Vin is less than LTP; the output will
switch from -Vsat to +Vsat which is shown in the graph. The difference between UTP-LTP is
called hysteresis. Hysteresis avoids false triggering of the circuit by noise. Hysteresis curve is
the plot of Vo versus Vin . Schmitt trigger circuit is used to convert any irregular wave into
square wave.
Procedure:
1. Check the components.
2. Setup the circuit on the breadboard and check the connections.
3. Switch on the power supply.
4. Give Vi= 10 Vpp / 1KHz sine wave.
5. Observe input and output on two channels of oscilloscope simultaneously.
6. Note down and draw the input and output waveforms on the graph.
Design:
UTP = +Vsat( R1/R1+R2)
Let UTP = +3V and LTP = -3V,
Vsat=+13V
UTP, +3 = +13( R1/R1+R2)
Let R1 = 1 KΩ
Then R2 = 3.3KΩ
Observations:
UTP =?
LTP =?
Негізгі бет Schmitt trigger | Using Op-Amp | Circuit Diagram | Breadboard Wiring| Output on DSO
Пікірлер: 5