Diodes refers to the devices which allows the current to flow in one direction in the case of the forward biased. The diodes usually provide great resistance to the current which flows when applied as the reverse biased. Zener diode refers to a type of diodes which allows the flow of current in both the forward and the reverse direction when applied as the reverse bias and the forward bias (Lin et al 2012). In this type of applications, the applied voltage is usually slightly above the breakdown voltage. This threshold voltage is usually referred to Zener breakdown voltage. This type of voltage can be referred to as the voltage at which the diode starts conducting in one direction which is considered to as reverse. The uniqueness is defined by its ability to allow the flow of current in a reverse way when the value of the voltage meets the standard values which is needed. The Zener voltage is the much talked about breakdown voltage. The value of the Zener voltage normally has higher value in the case of the standard values. The design of the Zener voltage is normally kept as low as possible (Yajun et al 2013). The breakdown is controlled in such a way that the diode is not damaged when there is reversal of the current whose value is slightly above the voltage of the Zener.
Aims and objectives of the experiment
The main aim of this experiment was to carefully research and analysis the workability of the Zener diode in the forward and reverse bias (M’Hamed, Torres, Reineix and Hoffmann 2011). With that some specific objectives were set to assist in achieving the main aim of the experiment and they include;
Materials and apparatus
Black Board and Jumper Wire
DZ = Zener diode,
Zener Diode (1N5232B)
RL= 1kW , Rs = 100W
VZ = VL, Vo = 5.6 V
Vin = 10 – 15 V, IL = 10 mA, RL=?
|
No. |
Description |
Quantity |
|
1 |
DC regulated power supply dual type of capacity 0-30V |
1 |
|
2 |
A digital Ammeter type of capacity 0-200mA |
2 |
|
3 |
Voltmeter(digital) 0-20V |
1 |
|
4 |
Wires for connection |
1 |
|
5 |
Decade Resistance Box |
1 |
Specifications of the Zener Diode (1N5232B)
Voltage for the breakdown=5.2V
Dissipation of power=0.75W
Highest forward current=1A.
Operations
The Zener diode refers to those diodes which allows the current to flow in both directions i.e. the forward and reverse directions. The uniqueness of this type of diodes is usually defined by their ability to allow the current to flow in a reverse direction the moment the value of the voltage meets a given value that is required. The value of the Zener voltage usually has a greater value in the case of a standard values (Kumngern and Junnapiya 2013). The design of the Zener voltage is usually kept as low as possible. The breakdown is normally controlled in such a way that the diode is not damaged when there is reversal of the current whose value is slightly above the voltage of the Zener. The most widely recognized qualities for ostensible working voltage are 5.1 V, 5.6 V, 6.2 V, 12 V and 15 V. We additionally convey Zener diodes with ostensible working voltage up to 1 kV. Forward (drive) current can have a range from 200 uA to 200 A, with the most widely recognized forward (drive) current being 10 mA or 200 mA. In the forward predisposition heading, the Zener diode carries on like a customary silicon diode (Choi et al 2011).
In the switch inclination bearing, there is for all intents and purposes no invert current stream until the point when the breakdown voltage is come to. At the point when this happens there is a sharp increment in turn around current. Fluctuating measure of switch current can go through the diode without harming it. The breakdown voltage or Zener voltage (VZ) over the diode remains moderately consistent. The most extreme switch current is constrained, be that as it may, by the wattage rating of the diode.
At the point when the diode is in the turnaround predisposition condition, the width of the exhaustion area is more. In the event that both p-side and n-side of the diode are delicately doped, consumption area at the intersection extends. In invert predisposition, the minority charge bearer current moves through intersection (Chiu et al 2010). As the connected turn around voltage builds the minority transporters secure adequate vitality to slam into the bearers in the covalent bonds inside the consumption area. Therefore, the security breaks and electron gap sets are created. The procedure ends up aggregate and prompts the age of an expansive number of charge bearers bringing about Avalanche Breakdown (Tani, Yamashita and Takahashi, Texas Instruments 2016).
Zener Diode as Voltage Regulator
The capacity of a controller is to give a consistent yield voltage to a heap associated in parallel with it despite the swells in the supply voltage or the variety in the heap current and the Zener diode will keep on managing the voltage until the diodes current falls beneath the base IZ(min) esteem in the turnaround breakdown locale. It licenses current to stream the forward way as typical, however will likewise enable it to stream in the turnaround heading when the voltage is over a specific esteem – the breakdown voltage known as the Zener voltage. The Zener diode extraordinarily made to have a switch voltage breakdown at a particular voltage. Its qualities are generally fundamentally the same as regular diodes. In breakdown the voltage over the Zener diode is near consistent over an extensive variety of flows along these lines making it helpful as a shunt voltage controller.
The motivation behind a voltage controller is to keep up a steady voltage over a heap paying little mind to varieties in the connected info voltage and varieties in the heap current. A run of the mill Zener diode shunt controller is appeared in Figure 3. The resistor is chosen with the goal that when the info voltage is at VIN(min) and the heap current is at IL(max) that the current through the Zener diode is at any rate Iz(min). At that point for every other mix of info voltage and load current the Zener diode directs the overabundance current subsequently keeping up a steady voltage over the heap. The Zener conducts the slightest current when the heap current is the most elevated and it leads the most present when the heap current is the least.
On the off chance that there is no heap obstruction, shunt controllers can be utilized to scatter add up to control through the arrangement opposition and the Zener diode. Shunt controllers have an innate current restricting favorable position under load blame conditions on the grounds that the arrangement resistor limits abundance current.
There are basically two types of the known regulations.
Line regulation
In this kind of the regulation, the load resistance and the series resistance are fixed values. The only value that is changing is the input voltage. The value of the output voltage will remain constant as long as the value of the input voltage is kept above the specific minimum value.
Load Regulation
In this kind of the regulation, the voltage of the input is fixed and there is variation in the value of the load resistance. The output volt remains the same. This is possible as long as the resistance of the load is kept constant and also kept above the specific value of the required threshold.
Experimental Procedure
In order to achieve the forward condition, the following steps were followed.
Zener diode as Line regulator
This was used in the case of the variations in the supply of the voltage.
Zener diode as load regulator
This was used in the variation of the connected load.
Results
VZ = 5.6 V.
VL = 5.6 V;Po = 500 mW ;
Is = IL + Iz = 10 + 89.29 = 99.29 mA
Vs = Vin – Vz
If Vin = 10 V;Vs = 10 – 5.6 = 4.4 V.
If Vin = 15 V,;Vs = 15 – 5.6 = 9.4 V
Use 15V,; ;
For Vin = 10
|
Vin(V) |
Vo(V) |
|
10 |
6.04 |
|
11 |
6.07 |
|
12 |
6.11 |
|
13 |
6.19 |
|
14 |
6.23 |
|
15 |
6.24 |
|
IL(mA) |
Vo(V) |
|
0 |
6.07 |
|
15 |
6.05 |
|
20 |
6.01 |
|
30 |
5.99 |
|
40 |
5.96 |
|
50 |
5.92 |
|
60 |
5.80 |
|
70 |
5.35 |
|
80 |
4.56 |
|
90 |
3.98 |
|
100 |
3.45 |
|
105 |
2.12 |
For Vin = 15
|
Vin(V) |
Vo(V) |
|
10 |
6.04 |
|
11 |
6.07 |
|
12 |
6.11 |
|
13 |
6.19 |
|
14 |
6.23 |
|
15 |
6.24 |
|
IL(mA) |
Vo(V) |
|
0 |
6.27 |
|
15 |
6.24 |
|
20 |
6.21 |
|
30 |
6.18 |
|
40 |
6.15 |
|
50 |
6.10 |
|
60 |
6.04 |
|
70 |
6.01 |
|
80 |
5.98 |
|
90 |
5.34 |
|
100 |
2.56 |
|
105 |
0.65 |
Graphical presentation.
Switching conversion
The devices that are analog in nature have very big range of regulators for switching and whose operation are based on the principle of step up and step down in the modes of the inversion, the devices have the ability to produce output voltage that is adjustable or one that is fixed already. The maximum output of the current is normally at the 2A(Anderson). The commonly available features at the regulation point include the following:
This kind of the family products are expected to reduce the number of the external components in the case of the space challenged uses (Lindner et al 2016).
There are several advantages of the high efficiency DC-DC switching ICs. Some of these advantages include;
The regulator for the switch may be used as an inductor, a power switch or as a diode to assist in the energy transfer from one input to the output. The basic components of the circuit for switching can actually be arranged so as to form a step down that is also called the buck converter, an inverter or the boost system also known as the step up
converter (Eom et al 2012). The addition of the control circuitry and feedback may assist in the regulation of the energy transfer and assist in the maintenance of the constant output. There is provision of the high switching frequencies that are known to be very efficient in internal switching of the other elements, the built in circuit protection that support a wide range of the applications and finally the board input ranges.
Experiment
Experimental Aims and objectives
To observe the operating characteristics of the boost, the buck and the buck-boost.
Materials and Equipment
Converter box of DC-DC
A 3-ph resistor load box
Fluke 43B power quality analyzer
Fluke 4mm Test pins
Banana Test Leads
Small screw driver.
Procedure
The following procedure was used in the laboratory for the process.
Buck-converter circuit
Buck-Boost Converter Circuit
The below circuit was considered
Diagram of Switching Power Conversion
Input Voltage = 10V (Don’t EXCEED 15V on this input)
Output Voltage = 5V
Load Current = 10mA
VL = 5.6V, IL = 10mA
|
Load Current IL (mA) |
Output Voltage (Volt) |
|
0 |
2.999 |
|
100 |
2.991 |
|
110 |
2.953 |
|
190 |
2.950 |
|
230 |
2.945 |
|
280 |
2.944 |
|
310 |
2.938 |
|
400 |
2.936 |
|
510 |
2.901 |
|
610 |
2.887 |
|
700 |
2.398 |
|
800 |
2.216 |
|
Input Voltage (Volt) |
Output Voltage (Volt) |
|
4 |
2.952 |
|
8 |
2.977 |
|
12 |
2.985 |
|
16 |
2.991 |
|
18 |
2.992 |
VL = 5.6V, IL = 10mA
Input Power = Output Power + Loss Power = 299.1mW + 71.72mW = 370.82mW
Output Current = 100mA
Output Voltage = 2.991V
Output Power = 299.1mW
Graphical representation.
Series (Transistor Regulator)
AB32 is normally considered the ready to use experiment board of the Transistor Series Voltage Regulator. This kind of the board is normally useful for those students that study the activities of the transistor as a regulator of the voltage in the series connection. Normally it may be used as the standalone unit that has external DC power supply.
Theory
Regulators are basically those circuits that are known to maintain the power supply of the voltages or the output of the current but within the limits that are specified. The design normally exploits the operation of the dc voltages depending on the areas of application. The voltage regulator circuits are addition to the basic power supply circuits whose components include the sections of the filter and the rectifier. The voltage regulator serves to provide the output that has got very little variation. The circuit of the regulator will sense changes and then provide compensation for the sensed changes. There are basically two types of the voltage regulators are normally categorized as the shunt or series depending on the location of the regulating elements.
In the diagram that has been labeled B, the suggested name series regulator is as a result of the connection of the regulating device in a series manner. As can be seen from the given diagram, it is clear that the regulator that is in series with the load resistance, RL. Also the fixed resistor that is marked as Rs is in series as well with the load resistance. Considering that the total current sometimes passes through this kind of the transistor, it is normally called the pass transistor. The other components that are known to be part of the circuit include the Zener diode of 5.6V and a current limiting resistor of 200ohms.It is important to remember that the Zener diode is one that will block the current until the specific value of the voltage is applied. The applied voltage is normally called the breakdown or just the Zener voltage. When the Zener voltage value is finally achieved, the conduction of the diode will be from the anode terminal to the cathode of the very diode.
In this kind of the voltage regulator, the transistor has a fixed value of the applied voltage that is commonly referred to as the reference voltage. The changes in the output of the voltage are detected and then corrected at the point of the emitter (Boylestad and Robert 2012) . The Zener diode will always assist in the establishment of the base voltage.
Experiment 1
Aims and Objectives
To study the Transistor series voltage regulator with the variable load resistance, RL and fixed input voltage.
Materials and Equipment
Analog board of AB32
Two digital mustimeters
Two patch cords of 2mm each
A DC power supply.
The circuit diagram was as indicated below.
Procedure
The following steps were followed in the experimental set up.
The power supply of +12V was connected at their respective positions from the external source.
One of the voltmeters was connected between the test point 1 and the ground so as to allow for the measurement of the voltage, in.
The ohmmeter was connected between the test point 4 and the ground and the set value of the load resistance Rl was placed at some fixed value of 1K (Kinsella et al 2014).
The 2mm patch cord was connected between the test point 2 and 3 of the components.
The voltmeter test point was connected at position 4 so as to allow for the generation of the output, V out.
The power supply was then switched on.
The exercise of varying the potentiometer from the input voltage of 0V to 9V was carried out while measuring the correspondence values of the output voltage, V out, the Zener voltage, Vz and also the forward biased voltage, VBE.
The patch cord was then disconnected from the points 2 and 3.
The procedure was repeated for confirmation of the accuracy.
Results and Calculations
The percentage of the regulation was obtained by the formula shown below.
% Regulation = [(VNL − VFL) / VFL] * 100
In which;
R = resistance in series VNL = no-load or open-circuit terminal voltage. VFL = full-load terminal voltage.
Results
The experimental results that were obtained indicated that the value of the fixed voltage ranged from 0V to 5. 54V.The percentage of the regulation was found to be 88.75%.
Experiment 2
Experimental aims and Objectives
To study Transistor Series Voltage regulator when the input voltage is considered variable and the resistance of the load is taken as the fixed value.
Materials and Equipment
Analog board of AB32
Digital multimeters
Patch card of 2mm
A +12 voltage power supply from the external source.
The applied circuit diagram
The 12 V power supply was connected to the indicated positions
The voltmeter was connected between the test point 1 and the ground so as to assist in the measurements of the input voltage.
The ohmmeter was connected between the test point 4 and also the ground while putting the value of the load resistance at RL maximum amount.
The two mm patch cords were connected between the test points 2 and 3.
The voltmeter was then connected between the test point 4 and the ground and this really assisted in the measurements of the voltage output (Xia, Chen and Broadcom 2015).
The potentiometer was varied after switching on of the power from as little value as 7V to as maximum as 9V
The corresponding values of the V out and the V Zener were measured.
Results
The results that were obtained from the experiment 2 indicated that for the network that had fixed value of the load resistance, the output of the voltage will always remain unchanged and very close to a value of 4.9V when the input voltage was from 7V to 9V.
Series (Buck Convertor)
Overview
The DC-DC converters are normally known to provide enough conversion of the DC voltage from one level to another level. The word Buck converter basically means that the converter takes an input current from a higher level of voltage like 36-42voltage from the solar panels to another level of say12Vdc for use in the equipment.
Theory of operation
The basic components of the buck converter are as indicated below. The voltage for the input is taken as a variable with no ripples. The switches of the electronics opens and closes at a rate that is fixed for example at a value of 100kHzThe duty cycle however is varied to give the output with designation of the V out. The capacitor is assumed to be very large to provide an output with less than 5% ripples. This basically means ripple free. In the normal cases of the operation, it is assumed that the circuit is in continuous conduction
It is important to note that 0.01 ? will be required at the negative terminal as given so as to assist in the measurement of the current at the point of the ouput.In oreder tpo have the overshoot reduced across the Vin termainal,a capacitor of the value of the 10 µF will be needed.The overshoot ios normally caused by the inductance.It is assumed that the circuit is basically lossless so as to ensure that the value of the output is equal to the vakue of the input.
Pin=Pout
When continous conduction is assumed,the circuit takes two states.The open switch is open and closed as illustaretd in the diagram below.
For Switch closed
For switch open.
In the closed switches, the biasing of the diode is reversed. The iL increases at the rate given below. The inductor however is charging properly.
When the switch is open, the iL will just continue to circulate through the diode and the diode is biased forward. The iL value decreases at the illustrated rate.
In the continuous conduction, the wave form below is obtained.
At the moments of the low amounts of loads the converter normally executes dissentious in the mode of the conduction. The third state is normally obtained during the all the power is offered by the system of the capacitor. The voltage that is across the conductor hence becomes zero.
A carefully crafted plan was created for the circuit layout as shown in the figure below on the piece of wood. The wire in red colour is the positive and the wire in black colure indicates the-ve terminal.
The diode was applied in the identification of the leads of the negative and positive values.
All the procedures for wiring were achieved as need.
The 10uF ripple current capacitor was connected across the terminal of the Vin.The polarity was not important considering that the capacitor was bipolar (Sawyers and Hewlett-Packard Development 2012).
The MOSFETsnubber capacitor was removed and discarded.
A 12 Vdc was connected to the wall wart of the dc jack so as to assist in the firing of the circuit.
The MOSFET firing circuit was connected to the buck converter. The wires were kept as short as possible. A 10 ? power resistor was connected to the output that is provided by the buck converter. The transformer was then connected to the DBR.
Conclusion
In conclusion, Diodes refers to the devices which allows the current to flow in one direction in the case of the forward biased. The diodes usually provide great resistance to the current which flows when applied as the reverse biased. Zener diode refers to a type of diodes which allows the flow of current in both the forward and the reverse direction when applied as the reverse bias and the forward bias. In this type of applications, the applied voltage is usually slightly above the breakdown voltage. This threshold voltage is usually referred to Zener breakdown voltage. This type of voltage can be referred to as the voltage at which the diode starts conducting in one direction which is considered to as reverse.
the overall practical session gave the insight of the ways of converting the AC power to the Dc power. This was considered was very essential in knowing since majority of the electrical appliances have this kind of circuits built in them. In addition, by considering that the majority of the electrical appliances usually expect power voltage of 120VAc. The knowhow of the conversion links to the inputs. This should be incorporated at the design phase. The inspiration behind the voltage controller is to ensure that there is a steady voltage over a heap having in account of the various that are connected info voltage in the heap current.
References
Anderson, F.G., Feilchenfeld, N.B., Harmon, D.L., Phelps, R.A., Shi, Y. and Zierak, M.J., International Business Machines Corp, 2013. Isolated Zener diode. U.S. Patent 8,492,866.
Boylestad, Robert L., and Louis Nashelsky. Electronic devices and circuit theory. Prentice Hall, 2012.
Chen, S.K., Chiang, W.L., Chiang, M.T. and Chang, C.H., Vishay General Semiconductor LLC, 2016. Thin bi-directional transient voltage suppressor (tvs) or zener diode. U.S. Patent Application 14/673,910.
Choi, S.S., Cho, D.H., Choi, C.J., Kim, J.Y., Yang, J.W. and Shim, K.H., 2011. Robust ESD protection for high brightness GaN LEDs using new TVS Zener diodes. Semiconductor Science and Technology, 26(5), p.055009.
Chiu, H.J., Lo, Y.K., Chen, J.T., Cheng, S.J., Lin, C.Y. and Mou, S.C., 2010. A high-efficiency dimmable LED driver for low-power lighting applications. IEEE Transactions on Industrial Electronics, 57(2), pp.735-743.
Eom, H., Lee, C.C., Yang, T.Y. and Yang, S., 2012, February. Design optimization of TRIAC-dimmable AC-DC converter in LED lighting. In Applied Power Electronics Conference and Exposition (APEC), 2012 Twenty-Seventh Annual IEEE (pp. 831-835).
Kinsella, C.E., O’Shaughnessy, S.M., Deasy, M.J., Duffy, M. and Robinson, A.J., 2014. Battery charging considerations in small scale electricity generation from a thermoelectric module. Applied Energy, 114, pp.80-90.
Kumngern, M. and Junnapiya, S., 2013, October. A CMOS four-quadrant current multiplier using electronically tunable CCII. In Advanced Technologies for Communications (ATC), 2013 International Conference on (pp. 366-369). IEEE.
Lindner, F., Luessem, B., Harada, K. and Leo, K., NovaLED GmbH, 2016. Organic zener diode, electronic circuit, and method for operating an organic zener diode. U.S. Patent 9,306,182.
Lin, Xin, Daniel J. Blomberg, and Jiang-Kai Zuo. “Zener diode with reduced substrate current.” U.S. Patent 8,198,703, issued June 12, 2012.
M’Hamed, B.B., Torres, F., Reineix, A. and Hoffmann, P., 2011. Complete time-domain diode modeling: Application to off-chip and on-chip protection devices. IEEE Transactions on Electromagnetic Compatibility, 53(2), pp.349-365.
Sawyers, T.P., Hewlett-Packard Development Co LP, 2012. Bi-directional control of power adapter and load. U.S. Patent 8,190,933.
Tani, T., Yamashita, A., Kusamaki, M. and Takahashi, K., Texas Instruments Inc, 2016. Bi-directional ESD diode structure with ultra-low capacitance that consumes a small amount of silicon real estate. U.S. Patent 9,337,299.
Xia, W. and Chen, X., Broadcom Corp, 2015. Zener diode structure and process. U.S. Patent 8,993,392.
Yajun, W.E.I., Collins III, W.D. and Steigerwald, D.A., Koninklijke Philips NV and Lumileds LLC, 2013. Zener diode protection network in submount for LEDs connected in series. U.S. Patent 8,400,064.
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