University of San Carlos

Nasipit Talamban, Cebu City

Department of Mechanical and Manufacturing Engineering

ME 327 ML

Basic Electronics Laboratory

Diode Applications

DC Power Supply DesignSubmitted by:

Mandawe, Christian Vincent J. BSME – 3

Submitted to:

Engr. Gene Fe Panes Palencia

Instructor

December 15, 2015

I. Introduction

In this experiment, it is all about the concept of certain diode applications. Specifically, it shows

the clipping and clamping of the circuit. It also shows the concept of a voltage multiplier circuit.

First, clipping circuit removes a part of the input signal without disturbing the input waveform.

From the word “clip”, it is holding a certain portion of the input signal. This circuit usually requires a

diode and resistors or capacitors. The best example of a diode clipper is the half wave rectifier. It

requires a single diode and a single resistor. There are two types of clipper circuit. The first one is the

series clipper circuit and the other one is the parallel series circuit.

Series clipper circuit has a diode in series to the load. The parallel clipper circuit has a diode in

parallel to the load

Other classification of a clipper circuit is the positive and negative clipper circuit. A positive

clipper circuit removes a portion of the positive input voltage. A negative clipper circuit removes or

holds a portion of the negative input voltage. There are special clipper circuit called Biased Clipper

Circuit which holds the input signal to some specified value. Clipper circuit can handle at different

waveform. It can be sinusoidal, triangular or a square wave.

Next, the clamping circuit is an electronic circuit that shift the voltage input to a different DC

level. From the term “clamp”, it is raising or lowering the reference level of the voltage input. It does not

alter or change the form of the applied signal. In this circuit, it requires a diode, capacitor and resistors.

It has a capacitor placed in series with the input. The diode and the resistor are placed in parallel with

the voltage input and voltage output.

There are types of clamping circuit. It can be positive or negative. It can shift the wave to a

positive value through the positive clamper circuit. It can also shift the wave to a negative value through

the negative clamper circuit. There is another type which shifts the waveform to a specified value. It is

called Biased Clamper Circuit.

Lastly, the voltage multiplier circuit increases the input peak voltage by a certain factor. It can

double, triple or quadruple the voltage input. This is very important in certain application where there is

a need to increase the voltage output from a certain voltage input.

II. Circuit Operations

Figure 1 Series Negative Clipper

In this circuit, use one 1N4002 diodes and 1K Ω resistor. Place the diode first and

place the resistor. Put the channel 1 wire of the oscilloscope on before the silicon diode. Put the

channel 2 wire after the silicon diode. Set the appropriate volts per division and time per division.

Record the data.

Figure 2 Parallel Positive Clipper

In the circuit, use the same electric components. Put the channel 1 wire before the resistor.

Place the channel 2 wire after the resistor. Put the ground of each wire after the diode. Set the

appropriate volts per division and time per division. Record the graph from the oscilloscope.

Figure 3 Positive Clamper Circuit

In the circuit, use the same type of diode. Use 100 KΩ resistor. Place the diode and the resistor

parallel with the AC voltage source. Place the capacitor in series with the voltage source. Put the

channel 1 wire before the capacitor. Put the channel 2 wire before the resistor. Please take note of the

polarity of capacitor and the diode. Set the appropriate volts per division and time per division. Record

the graph from the oscilloscope.

Figure 4 Negative Clamper Circuit

In the circuit, use the same type of electronic components. Assemble the circuit shown above.

Invert the polarity of the capacitor and the diode. Put the channel 1 wire before the capacitor. Put the

channel 2 wire before the resistor. Please take note of the polarity of capacitor and the diode. Set the

appropriate volts per division and time per division. Record the graph from the oscilloscope.

Figure 5 Voltage Multiplier Circuit

In the circuit, use four silicon diodes and 4 capacitors. Assemble it as shown above. Please

take note of the polarity of the diodes and the capacitors. Place the voltmeter before the first capacitor

and before the fourth diode. This is to measure the triple output voltage in this circuit. To determine the

quadrupler output, place the voltmeter after the voltage source and after the fourth capacitor.

III. Results and Discussions

A. Clipping Circuit

Part I Negative Series Clipper

In the negative series clipper, the positive output voltage is recorded. When the current

changes direction, it blocks the current flow. Negative series clipper removes the negative voltage

output.

Part I Positive Series Clipper

In the positive series clipper, the negative output voltage is recorded. When the current

changes direction, it blocks the current flow. Positive series clipper removes the positive output voltage.

It leaves the negative output voltage.

Part II Positive Parallel Clipper

In the positive clipper, the negative output voltage is recorded. When the current changes

direction, it is blocked by the diode at reverse bias condition. It produces this type of wave where the

positive output voltage is removed.

Part II Negative Parallel Clipper

In the negative parallel clipper, the negative output voltage is removed. When the current

changes direction, it is blocked by the diode at reverse condition. This cause the zero recorded voltage

as shown in the graph.

B. Clamping Circuit

Part III Positive Clamper Output

In the positive clamper circuit, the graph shifts upward. It still has the same peak-to-peak

voltage. This is caused by the capacitor.

Part III Negative Clamper Output

In the negative clamper circuit, the graph shifts downward. It is located at the negative portion

of the voltage. It still has the same peak-to-peak voltage. The shifting was caused by the capacitor. The

shift direction was affected by the orientation of the capacitors and diodes.

C. Voltage Multiplier

V @ C2 = 32.2 V

V @ tripler output = 48.7 V

V @ quadrupler output = 64.6 V

Based on the data, the voltage input triples and quadruples. This is caused by the capacitors

and the diodes in the circuit.

IV. Summary and Conclusion

One of the objectives of this experiment is to observe and test the different types of diode

clipper circuit. Based on the description of a clipper circuit, it holds a portion of the input signal. One

example is the half-wave rectifier. It requires a diode and a resistor. Based on the experiment, the

negative series clipper removes the negative portion of the input signal. The positive series clipper

removes the positive portion of the input signal. In a parallel circuit, it is still the same. The parallel

positive clipper removes the positive portion of the input signal. The parallel negative clipper removes

the negative portion of the input signal. The holding of the portion of the input signal is caused by the

diodes. In a forward bias condition, it allows current flow. However, it blocks the current at the reverse

bias condition.

In the clamping circuit, it shifts the reference level of the input signal. It can either shift to the

positive portion. This is called the positive clamping circuit. It can shift to the negative portion. It is

called the negative clamping circuit. It can shift to specified value. It is called the biased clamper circuit.

One of the distinctions with the clipper circuit is that it has a capacitor placed in series with the voltage

input. The capacitor stores energy. In a forward bias condition, the capacitor first absorbs the peak

voltage from the voltage source. Then, the voltage source goes through the reverse bias condition

where the current is block by the diode. Afterwhich, it returns to the forward bias condition. The voltage

input from the source adds up with the voltage input from the capacitor which is the energy stored in the

previous forward bias condition. The absorbed voltage is the same as the peak voltage of the voltage

source. This would double the voltage thus shifting it on the positive direction or on the negative

direction. For this capacitor and resistor, it requires a higher time constant T = RC. The purpose of this

one is not to let the capacitor discharge when the current is in the reverse bias condition. The purpose

for this is that it has still its own energy when the current is in forward bias condition. This would cause

the summing up of the voltages from the source and the capacitor. This can cause shifting of the signal.

In the voltage multiplier, it doubles, triples or quadruples the voltage input. There is a need to

focus voltage double to get the concept of this voltage multiplier.

Based on the figure above, this is a voltage multiplier circuit. In a forward bias condition, current

flows to C1 and D1 it cannot pass through D2 since it is reverse bias. This would charge C1. When it

alters its direction, the current cannot pass through D1 since it is reverse bias. It would pass to C2 and

charging it up. This would charge up with the voltage on C1. Through this process, the voltage output is

doubled due to the stored energy of both capacitors. The voltage of the capacitor is equal to the voltage

peak of the voltage source. Since the C1 store the energy and have the voltage equal to the voltage

peak of the voltage source, this would give C2 twice the voltage. Since the voltage output is parallel

with C2, the voltage output is equal with the voltage from C2. This would cause the voltage output to be

twice the voltage input.