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DIODE - Limiter
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Aim:

To design and study a diode limiter circuit. 

Components required:

   Function generator, CRO, resistor, Diode, connecting wires. 


Vlab Specifications Taken:

Diode limiter circuit design has been implemented on the virtual breadboard using following specifications:

·         Function generator: Selected wave with following specifications:
Frequency = 100Hz (Any frequency between 50 Hz to 1KHz can be given) 
Wave type: Sinusoidal Wave. 
Amplitude: Varying between 5 to 15 volts. 
Duty cycle = 50% 
·         Resistor R2:10 K
·         Diode:


Theory:

The diode limiter also called Clipper as it is used to limit the input voltage. A basic diode limiter circuit is composed of a diode and a resistor. Depending upon the circuit configuration and bias, the circuit may clip or eliminate all or part of an input waveform. 
It limits the output voltage to a specific value. 
The circuit shown in the figure1 illustrates a typical parallel positive and negative limiter circuit. It is called the parallel positive and negative limiter circuit because the diode is in parallel with the output, and the circuit clips or alters the positive and the negative portion of the input waveform. 
The parallel positive and negative limiter is constructed from two diodes in parallel. During the positive alternation, one diode is forward biased. The other diode is forward biased during the negative alteration. 

Figure 1: Parallel Positive and Negative Limiter


Procedure:

1.     Connect the circuit as shown in the circuit diagram.
2.     Give the input signal as specified.
3.     Vary the amplitute of the input signal to verify the voltage limiting of the circuit.
4.     Note down the outputs from the CRO
5.     Draw the necessary waveforms on the graph sheet.


Observations:

1.     Observe the output waveform from CRO. A sine wave with a high amplitude (Voltage) is clipped.
2.     Measure the amplitude of the output wave from on the CRO screen.
3.     Compare the calculated output voltage with the ecperimentally observerd voltage from the output waveform.
4.     Observe output of the limiter circuit using different input voltage value.


VLab Observations Obtained:

1.     After Clicking on function generator icon on the left of the Vlab live environment page, set the frequency, amplitude and the type of waveform on function generator.
 
2.     Select sine wave on the function generator, click on the frequency button and then set frequency100Hz. (The frequency can be set to any value between 50 Hz to 1Khz for this experiment)
 
 
3.     Click on the amplitude button and select the amplitude of the sine wave, for example 10V.
 
 
4.     Check graph
 
 
 
5.     Circuit has been designed on the virtual breadboard with the help of procedure.
 
 
6.     Then on clicking on Run icon, the output waveform generated and the input can be observed on the CRO screen. CRO web page can be opened using icon oscilloscope at top left on the live experiment page.
 
 
7.     Click on measure. Then one can observe options like source, select, measure.

=>Click on source and select 4 i.e. the input wave.
=>Click on select and select the parameter to be measured, for example select frequency or amplitude.
=>Click on measure to get the frequency and amplitude of the input waveform.

It comes out to be Frequency: 100Hz, amplitude: 9.85V
8.     Now observe the amplitude of the output waveform.

=>Click on source and select 1 i.e. the input wave.
=>Click on select and select amplitude.
=>Click on measure to get the amplitude of the input waveform. 

The output voltage comes out to be 1.124V. 
9.     Observe the output wave form by varying the amplitude of the input sine wave.
 
 
Result:

The diode limiter circuit is designed and been studied successfully. 
 

Cite this Simulator:

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