Series Pass Voltage Regulator From Discrete Electronic Engineering Essay

serial Pass potential complete governor From Discrete electronic Engineering EssayThe objective of this project was to construct and design a 9V 0.3V, 1A serial publication track potential governor from decided electronic parts. The electromotive force governor moldiness exhibit a emf normal of 5% or better and should be supplied with a dc enter potential drop. The governor hitch was required to include a way to unplug the lodge from the regulator if the accuse certain exceeded 1A or if the temperature of the serial publication pass member exceeded 40C.It was requirement to measure for all(prenominal) one argument of the circuit and turn it from an parallel of latitude to a digital signal. This signal would moodyer up entropy necessary to parade the values on the Spartan III FPGA ripening Board.The quantitative disclose was not to carry any zeros leading a number, unless it unnatural the value. Also, the display was to be cyclic, alternating at 5 sec ond intervals.The circuit was designed, built and tested. It produced 9.03V return and 1.02A by dint of a 9 cargo. The cut- run into protection worked as well as the variable perception circuitry. The physical contactage of the analog and the digital components, however, remain incomplete.ContentsLIST OF FIGURESLIST OF TABLESLIST OF ABBREVIATIONS AND SYMBOLSSymbol interpretationADCAnalog to Digital convertorOp-ampOperational AmplifierV potentiality/VoltsI on-line(prenominal)RResistanceAAmpereOhmC grade CelsiusFFaradICCollector latestIBBase CurrentVBEBase-Emitter electric potentialLUTLook Up plug-inBCDBinary Coded DecimalMUXMultiplexerCLK quantifyDPDTDouble Pole Double ThrowFPGAField Programmable Gate alineTable List of Abbreviations Contained in this ReportINTRODUCTIONCommercial occasion is usually distributed with an AC supply. An unregulated potential drop such as this could front damage to many household appliances and electronic devices. on that transferfore it is a safety device hazard.A potency regulator is a device that maintains a relatively constant take potentiality for a varied arousal potential. It functions by comparing the railroad siding potential difference to a fixed reference and minimizing this struggle with a negative feedback loop.The aim of this project to design a serial publication pass potency regulator with an production of 9 0.3V and regulation of at least 5%. It should be able to disconnect the pro fane from the regulator for temperatures exceeding 40C and a menstruum greater than 1A. victimisation A/D change overers, these values ( product regulator potency and flow, temperature of the series pass junction transistor) were converted to digital format and displayed on the Spartan III FPGA Development Board. apiece value received from the analog component should be displayed with no unnecessary leading zeroes. The display had to alternate between different variables of voltage, original and temperature.The Digital Component of this project was designed in Xilinx ISE 7.1i, and the necessary tests were carried out. A User Constraints file was realised, which allowed for the programming of the FPGA Board.BACKGROUND THEORY AND LITERATURE brush upUsing an unregulated place supply is unfeasible for most tasks. This is be evidence as the accuse flowing increases, the ripple voltage increases and the DC output voltage moderates. The voltage regulator greatly compacts ripple and produces a steady output voltage for a work of commentary voltages.Different casings of voltage regulators stupefy different functions. There be deuce main types, transfer and series voltage regulators.Shunt Voltage governorFor a shunt voltage regulator, the regulating device is placed in parallel with the load. A opposition is placed in series with the load and the unregulated supply. The latest is varied through the control element depending on the load incumbent. This captures a volt age drop crossways the ohmic resistance in series, maintaining a constant load voltage. (Prof. Gift, 2012) habitus Shunt Voltage governorShunt Voltage Regulator Example Zener Diode Regulator recruit Zener Diode Voltage RegulatorThe zener diode is a semi-conductor diode designed to operate in the reverse-biased region. In forward bias, it functions as a normal diode but when in reverse bias, it breaks down for voltages exceeding the breakdown voltage, or zener voltage. For operation in this region a live Iz is required where the limits being the minimum and supreme veritable for the diode to operate without breaking down. (Prof. Gift, 2012)Series Voltage RegulatorFor a series voltage regulator, the regulating device is placed in series with the load and the unregulated supply. (Prof. Gift, 2012) The output voltage is sampled by a circuit that provides a feedback voltage to be compared to a reference voltage. If the output voltage increases, the comparator circuit provides a co ntrol signal to cause the series control element to decrease the amount of the output voltage, thitherby maintaining the output voltage. If the output voltage decreases, the comparator circuit provides a control signal to cause the series control element to increase the amount of the output voltage. (Electronic Devices and rotary Theory 7th Ed.) forecast Series Voltage RegulatorThere are different circuit topologies for the series voltage regulator. These will be examined next.Simple Series transistor RegulatorTo improve the current mental object of the zener diode regulator, a transistor is use in the emitter follower configuration. This acts as the series control element. The accumulator is supplied by the regulated voltage. The transistor reduces the load current capacity of the zener by a chemical element of the transistor current net profit. The zener voltage is therefore produced at the emitter. The equation IC = IB is utilise to link the collector current and the base current. Due to heights current gain, until straight very life-sized changes in IC result in that small changes in IB. This representation IZ is mostly stable. The input voltage must be greater than the diode voltage to ensued proper transistor bias. (Prof. Gift, 2012) descriptor Simple Series Transistor Voltage RegulatorIZ current through the zener diodeIC collector currentIB base currentDiscrete Voltage RegulatorA transistor Tr2 is affiliated as the series pass transistor and another one Tr1 acts as the defect amplifier. In the single transistor regulator output ripple voltage is low, but the output voltage still varies. This is due to the VBE/IC indication of the transistor. Feedback is use to correct the output. This amplifier compares the sampled voltage with a reference voltage in orderliness to generate a signal proportional to the difference. This is use to stupefy the series pass element, which wherefore varies the output voltage such that the wrongdoing i s reduced and the output voltage regulated. mannequin Discrete Transistor Voltage RegulatorThe voltage crossways the series element is (Vin Vout). The input voltage to the error amplifier is Vout Vref, where .The output voltage crosswise the series element is an amplified rendering of the input voltage,. If Vref is constant, . This is the stability factor.This operator that the ripple voltage is reduced by a factor of . The high-pitcheder the loop gain, A, the better the regulator performance. A is gain of error amplifier.The resistor R can be connected to the regulated side of the circuit to improve the design and decrease ripple voltage. Also, a capacitor may be placed in parallel to the Zener diode. Another capacitor can be placed crossways the output removing output noise and input impedance at high frequencies. A Darlington oppose may be employ as the series element. This has two transistors in a single package. The Darlington Pair increases the current gain of the se ries element, making it able to supply a larger load current if required. (Prof. Gift, 2012)Operational Amplifier Series Voltage RegulatorIn order to improve the regulator performance, the loop gain A is increased. A simplistic method of doing this is to replace the transistor error amplifier with an operational amplifier as shown in figure 6. The operational amplifier compares the reference voltage of the zener with the feedback voltage sampled by resistors R1 and R2. The Darlington Pair design is employ here and R3 connected to the regulated supply to reduce the ripple voltage. The operational amplifier (op amp) must be supplied by the unregulated input voltage. (Prof. Gift, 2012) work Operational Amplifier Series Voltage RegulatorSTANDARDSCertain standards were considered in the undertaking of this project. These areISO 90011994 Quality Systems Model for Quality Assurance in be after, Development, Production, Installation and Servicing (http//www.ttbs.org.tt/)TTS 620 2008 Occupational Safety and Health pretend discernment Requirements(http//www.ttbs.org.tt/)BS QC 7903041994 Specification for harmonized system of quality assessment for electronic components. (http//www.standardsuk.com)RISK ASSESSMENTPossible Hazards15V supply voltage. Risk of electrical shock, destroy and death.Solder fumes present. Dangerous if inhaled.The heat generated by the proponent resistor could cause burns.The tip of the soldering gets very hot and could cause relentless burns or start a fire.Clipping wires and leads may cause them to be projected into eyes and face.Steps Taken to Avoid RiskEnsured that student was properly grounded. Proper clothing and footwear were worn. No grand hanging jewellery or hair.Before energising a circuit, it was analyze by a technician.Tested conductors before handling them.Exhaust fan present in lab. Regularly stepped outside for fresh air.Clipped wires away from face of anyone present.DESIGN APPROACH AND METHODOLOGYProject Requirement s proveing and take a 9V 0.3V, 1A Series Pass Voltage Regulator using discrete electronic components.Regulator must have a voltage regulation or 5% or better and must be ply by a dc input voltage from a science lab index number supply. In addition, the regulator must incorporate temperature and over current sensing circuits which would disconnect the load from the regulator, for temperatures and currents exceeding 40 degrees centigrade and 1 A singlely.The output regulator voltage and current, together with the temperature of the series pass transistor must be converted to digital format using A/D converters and displayed on the Spartan 111 FPGA Development Board when take awayed. The following specifications must be met for the display of the variables1. The wholes of all variables are to be displayed along with the respective reading.2. The voltage is to be displayed to 1 denary point.3. The current is to be displayed to 2 decimal points.4. The temperature is to be disp layed as a whole number.5. The display of the readings for voltage, current and temperature are to automatically appear in a cyclic manner, with all(prenominal) reading being displayed for 5 seconds.6. All leading zeros are to be suppressed. (ECNG 2004 soma Project Description)This design had both an analog and a digital component.ANALOG COMPONENTThis component involved the design and construction of the Series Pass Voltage Regulator and the sensing circuitry to detect current, voltage and temperature. These demodulators were constructed to electrical pass along the values necessary for the digital component. Analog to Digital converters were designed to convert the analog output from the current, voltage and temperature sensing circuits to digital format so as to be to be read by the Spartan FPGA Board.Design of the Operational Amplifier Series Voltage Regulator participate Circuit draw of the Operational Amplifier Series Voltage RegulatorThe regulator was powered by a DC in put voltage from a laboratory power supply.The voltage apply in the design process for the purpose of tally was 15 volts.Choosing the Zener Voltage and Zener CurrentThe Zener Voltage, Vz was supplied by the Zener Diode, D1 as shown in Figure 7 above. The Zener Voltage was used as a reference voltage by the Operational Amplifier. The op amp is functioning as a derived function amplifier in this situation. The difference between the inputs at the inverting and non-inverting terminals is amplified.Gain,The output voltage, VZ zener voltageVz should be high enough so that gain would not decrease to get to the required output.If Vz was too high, i.e. the output voltage, no current would flow through D1. An appropriate value between 0V and 9V was elect, VZ = 4.8V.The IN4732 Zener Diode was chosen and the specification pall for this model was obtained. The specified test current was 53mA, and the chosen value was 40mA. This was chosen to ensure proper bias.Calculating Resistor R3The r esistor R3 was in series with the Zener Diode. Therefore, the current through them is the homogeneous.A blow resistor was chosen as it was the closest one in value available in stores.R3 = 100Calculating Resistors R1 and R2Resistors R1 and R2 formed a potential divider providing the inverting input of the op amp. This sampled the output and sent it to the error amplifier. If the value of the output changed from the designed, the voltage drop crosswise the resistors would change and the op amp input voltage would change, producing an error voltage at the output of the op amp. This error voltage will either turn on more or turn off more Transistor Tr1 and in effect Tr2 as well.The output voltage, Vo is related to the Zener Voltage by the equation beneath. change Vo = 9V and Vz = 4.8V,Therefore,If R2 chosen to be 10k, thenTherefore, R1 = 8.8k and R2 = 10k.Choosing an Operational AmplifierThe LF351 op-amp was chosen for this design. It only undeniable to function as a differential amplifier.Choosing the Series Pass TransistorThe required output current was 1 Ampere. Therefore the maximum collector current of the series pass transistor had to be greater than 1 A. high power transistor was needed, but the current gain of power amplifiers is low (approximately 40). The base current and collector current for a transistor are related by the following expression.Substituting Current gain, hfe = 40 and Ic = 1 A,The LF351 op amp could not supply this base current. A Darlington Pair arrangement was used instead. Darlington Pairs have high current gain. The high power transistor chosen was TIP31C, packaged in a TO-220 Case. The current gain, hfe1 of this transistor was specified to be between 10 and 50, so a value of 30 was used.An NPN medium power transistor, BFY51 in a TO-39 coat package, was chosen for Tr2 in Figure 6. The current gain, hfe2 was found to be 123.Hence, add up current gain of the Darlington Pairhfe1 - hfe2, i.e. 30 - 123 = 3690.Substituting Current gain, hfetotal = 3690 and Ic = 1 A,Design of the Voltage signal detection CircuitThe purpose of the Voltage Sensing Circuit was to determine the output voltage of the regulator and pass on this voltage to the Analog to Digital Converter input. The Analog to Digital Converter (ADC) chip (ADC08040 IC) had a reference voltage of 4.5V. The maximum voltage mathematical was 9.5V. Hence if the voltage output was 9.5V, the ADC08040 input voltage should be 4.5V.VO had to be stepped down by a potential divider before it could be sent to the ADC08040. It was stepped down by a factor of .Let R1 = 1k, then R2 = 1kThis voltage was sent to a social unity Gain Voltage attendant (Figure 8) and was input to the ADC circuit. (Prof. Gift, 2012)Voltage Sensor.bmpFigure Voltage Sensing CircuitDesign of the Current Protection CircuitThe purpose of this was to disconnect the load from the regulator when the current flowing through the load surpassed 1A. The protection circuit monitored the load curr ent and sent a signal to a device to disconnect the load, when the current rose to over 1A. A 1 shunt was used in series with the 9 load resistor. The shunt voltage was used to determine cut-off.An instrumentation amplifier was chosen (INA114AP) to compare the temperature sensor voltage and a potential divider voltage. The shunt voltage was amplified to increase chances of accurate finding of when to disconnect the load. A potential divider was constructed to deliver a4V, and the shunt voltage was also amplified to 4V.Potential DividerWhich employsLet R1 = 20kThe voltage from the shunt was amplified to 4V as well, and this was done by an op-amp and two resistors set up in the non-inverting refinement configuration shown below. The reference used to be amplified was 0.9V from the shunt, as this was the value which, if exceeded, cut-off and disconnect of the load was supposed to occur.For an non inverting amplifier,Vo = 4V, Vi = 0.4V,AndLet R1 = 2.4k, R2 = 8.2k.Temperature Amp I nput to INA.bmpFigure Circuit for Comparison and finding of Cut-offWhen both inputs have the same voltage crossways them, the instrumentation amplifier would have an output of zero. The transistor in Figure 10 would be turned off and the base would be at 0V.The transistor used was a 2N3904 (Ic = 200mA). If the output is non-zero, the base would be determined by a voltage and the transistor will be ON.When the output is zero (same inputs) the transistor would be OFF and the relay race roll would be grounded through the transistor. Current would flow through the coil, producing a magnetic field, and the relay would latch.When the instrumentation amp inputs are different, the output would saturate at +Vcc, i.e. 9V. The coil would an equal voltage at either end and so would have no voltage drop across it, meaning no current flowing through it. The relay is effectively OFF. There is a commonly Open (N.O.) Switch between pins 2 3, and 7 5 of the relay as well as Normally Closed (N.C.) Switches across pins 2 3 and 7 6. The N.O. switches close and the N.C. switches open when the relay latches. The load was connected across the N.C. pins. When the instrumentation amp has the same inputs, (zero output), and there is a voltage drop across the coil, current flows and the relay latches, disconnecting the load from the circuit.The relay had a rated voltage of 6V and the coil had a measured resistance of 70.5. The relays, however, were actually found to latch at a voltage of 3.2V. Therefore for calculation purposes 3.5V is used = 49.6mA was needed to latch the relay.A potential divider was used to provide the required voltage for the relay.For a resistor R3,This caused a voltage drop across the coil, larger enough to activate the coil when necessary.The voltage across resistor R3 is minded(p) by,For Ic = 49.6mA,The Base Current of the transistor is given byFor Ic = 49.6mA, and hfe = 100,To bias the base of the transistor for the 9V output of the op-amp,A 16k res istor was used. This would change VBE of the transistor. The new VBE was well within the operating range required for the resistor.Temperature Cutoff.bmpFigure Current Protection CircuitDesign of the Current Sensing CircuitThe Current Sensing Circuit determined the voltage regulator output load. This value of current would be received by the ADC input. The ADC chip (ADC08040 IC ) was 4.5V. The Current LUT could convert a maximum of 1.29A. This means when the regulator reaches 1.29A, the ADC will be at 4.5V.A 1 shunt resistor was placed in series with the load. The 9V regulated output would now be applied to a combined load of 10.Voltage drop across the shuntThereforeThe output voltage across the shunt is 0.9V. This will correspond with the maximum voltage which will give all 1s at the ADC output. Thus the voltage must be stepped up using a non-inverting op-amp. The voltage of 0.9V was stepped up to 4.5V.This means the gain is = 5Let R1 = 2k . Therefore, R2 = 8kThe potential divider voltage was passed through the amplifier and then input into the ADC.Current Sensing Circuit.bmpFigure Current Sensing CircuitDesign of the Temperature Protection CircuitThis disconnects the load from the regulator when the temperature of the Power Transistor (TIP31C) reached 40C. The Power Transistor temperature was monitored and at 40C, a signal would be sent from the circuit to a device, disconnecting the load.The LM35DZ was chosen. Its sensitivity was 10mV/C. At 40C, the temperature sensor output would be 0.4V.An instrumentation amplifier (INA114AP) was chosen to compare the temperature sensor voltage and the potential divider voltage. For a more accurate determination of the load, the temperature sensor output voltage was amplified. The potential divider delivered a voltage of 4V, and the sensor output voltage was also amplified to 4V.ThereforeLet R1 = 20kAn op amp and two resistors were used to make up a non-inverting amplifier in order to set the temperature sensor voltage to 4V. The reference voltage was 0.4V, since it is at this point cut-off should take place.For a non-inverting amplifier , ,Let R1=1k and R2=9k,Temperature Amp Input to INA.bmpFigure Amplifier Circuit for Comparison and Determination of Cut-off.When both input voltages are the same, the amplifier output would be 0V, turning off the transistor. (No VBE present). A 2N3904 transistor was used (Ic = 200mA), so the current would be large enough to latch the relay.If the amplifier output is not 0V, there would be a voltage drop across the base and the transistor would be ON.When the amplifier output is 0V, the transistor would be OFF, grounding the relay, causing current flow in the coil, latching the relay. When the amplifier inputs are at different levels, the output saturates at +Vcc = 9V. Equal voltages live on at both ends of the coil, so no current flows hence the relay is OFF. A Normally Open (N.O.) Switch exists across pins 2 3, and 7 5 of the relay. Normally Closed (N.C.) Sw itches exist across pins 2 3 and 7 6. The N.O. switches close and the N.C. switches open upon latching. Consider this load connected across the N.C pins and the amplifier has equal inputs. The amplifier output is 0V, causing a voltage drop across the relay coil, causing current flow and latching of the relay. It follows then that the load is befuddled from the circuit.For a resistor R3,R3 was used to activate the coil by creating a voltage drop across it.For Ic = 49.6mA,For biasing,A 16k resistor was used instead.Temperature Cutoff.bmpFigure Temperature Protection CircuitThis circuit was designed to relay the temperature of the power (TIP31C) to the ADC input. The ADC chip (ADC08040 IC ) reference voltage was 4.5V. The Temperature LUT could convert up to 129C. At this temperature, the ADC should be 4.5V. A Temperature Sensor (LM35DZ) in a TO-92 package used to determine the temperature. This had a sensitivity of 10mV/C. At 129C, VO = 1.29V.Sensor output voltage was stepped up us ing a non-inverting op amp by a factor of, Let R1 = 1k . R2 = 2.49k 2.5kThe sensor voltage was amplified and input into the ADC.Temperature Sensing Circuit.bmpFigure Temperature Sensing CircuitA copper strip board was used to build the voltage regulator circuit since the solderless breadboard could only take up to 0.5A.Inputs Voltage Supply of 15V Outputs Voltage Sensing OutputOV Ground modulate 9V OutputTemperature Sensing VoltageA voltage follower was used to buffer the output. The circuit was constructed as seen in figure 15Figure Complete Sensing and Cut-off CircuitDESIGN OF THE ANALOG TO digital alteration CIRCUITAn 8 bit representation was used with reference to the 4.5V signal. The analog signal was converted to a digital signal from the 3 sensing circuits using the schematic shown below. Analog to digital conversion was done using the. A resistor pack was used to provide over current protection. This circuit was built and tested for each of the three sensing circuits. A combination of LEDs was used for the input of the analog voltage. AD Converter Circuit.bmpFigure Schematic for ADC control configurationOp amps were used to buffer the inputs. The outputs were mapped onto the respective pins of the 40-pin IDE tune used to interface with the Spartan III Board.Figure 40 pin tumbler Expansion Connector (Spartan III Toolkit Datasheet)Data was transmitted using these pins to the ADC.DIGITAL COMPONENTThe FPGA board was programmed so as to use the Seven separate debunk. Xilinx ISE 7.1i was used to design and construct the display for all the variables.Design of the canonic Display UnitMultiplexers, Frequency Dividers, a Look up Table Device and a Binary Coded Decimal to 7-Segment Converter were used to create the Display Unit.The 16-bit 31 MultiplexerMultiplexers may have more than one input but usually have one output. A combination of amount is assigned to each input pin. Using these combinations, the respective input entropy is sent to the out put pin. Therefore the bits that are chosen which input data set to display. In this design, two multiplexers were used, a 4-bit 41 and a 16-bit 31 multiplexer. 31 means 3 data inputs, 16- bit means each input is of 16 bit capacity.16bit3to1muxschem.bmpFigure Schematic plat of a 16-bit 3 to 1-line MultiplexerThe 4-bit 41 MultiplexerThe 4-bit 41 multiplexer can handle up to four-spot-spot combinations of inputs. To select which input is displayed, two bits are necessary. The output was a bus of width 4 bits. It split the 16 bit output into four sets of 4 bits. The 4-bit 41 multiplexer is shown in figure 19.4bit4to1mux.bmpFigure Schematic Diagram of a 4-bit 4 to 1-line MultiplexerBinary Coded Decimal (BCD) to 7-Segment Display UnitThe BCD unit accepts four bits of data, e.g. D3D2D1D0, and determines which segments of the 7-segment display to turn on and off so as to represent the value of the input data. Figure 20 shows a 7-segment display. This type of display is common in elect ronic equipment e.g. calculators, microwaves, digital clocks. The Minimum Expressions for the BCD areSeg_a = D3D2D1D0 + D2D1D0 + D3D2 + D3D1Seg_b = D2D1D0 + D2D1D0 + D3D2 + D3D1Seg_c = D2D1D0 + D3D2 + D3D1Seg_d = D2D1D0 + D2D1D0 + D2D1D0 + D3D1 + D3D2Seg_e = D0 + D2D1 + D3D1Seg_f = D3D2 + D2D1 + D1D0 + D3D2D0Seg_g = D3D2 + D3D1 + D2D1D0 + D3D2D1For each expression, logic gate circuits were created. Each segment was then used to build the final BCD to 7-Segment Converter. The combinations of segments that would form the values were organised.The Look-Up-Table (LUT)This was used to determine which display unit anodes were to be turned on and off. There were four somebody 7-segment displays. Each one had its own anode and as such could be controlled by choosing the anode of the respective display.lut.bmpFigure Schematic Diagram of a Look-Up-Table (LUT)Modulo 4 snack barThe Modulo 4 counter was used to perform automatic cycling of the anodes to be displayed. Only one anode was on at a time for each different combination.Moduloo4counter.bmpFigure Schematic Diagram of a Modulo 4 tabulatorFor multiplexed displays, the entire display is not lit up as the same time. The characters are made up of segments which, under certain conditions, become active. Each character is displayed one at a time. Switching of characters takes place so fast it appears that all the displays are on at the same time. The move of switching is called the frequency divider (in this case 1kHz). This activates the modulo 4 counter which causes the LUT to tell apart one of four inputs to be chosen from the 4-bit 4 to 1 multiplexer to convey to the 7 segment display.The Combined Display UnitData Unit.bmpFigure Schematic Diagram of the Display UnitUpgrade of the Display Unit to display the Decimal PointThe LUT controls the switching of the anodes on the four 7 segment displays. Each 7 Segment Display has a decimal point that can be turned on or off if necessary. This was necessary in this proj ect when displaying voltage and current.For a voltage, the decimal point is on the 3rd anode, a2.09.0VFor a current, the decimal point is on the 4th anode, a3.0.99AThis means that the point will only be on when S0 and S1 select to display voltage or current, and when the third or fourth anodes are on respectively.The Essential Prime Implicants were chosen from a truth table and the minimise expression was produced as followsThe logical system Gate circuit was constructed as shown below and implemented in Xilinx ISE 7.1i. A Macro was then created and connected appropriately in the Updated Display Unit Schematic.Decimal Point Upgrade.bmpFigure Logic Gate Circuit for Decimal Point UpgradeUpgrade of the Display Unit to display the Units for each VariableThe Display Unit was upgraded a second time in order to allow the units of each parameter to showParameterUnitSymbol for UnitVoltageVoltsVCurrentAmperesATemperatureDegrees CelsiusCTable Parameters to be Displayed and their Respective UnitsThe BCD Converter had to be updated to ensure when certain select bits were chosen, the segments would align to form the unit symbol on the first anode.Since there are four select inputs, D3D2D1D0 , there are 16 possible combinations of these bits forming different outputs. 0000 to 1001 in binary star form represents 0 to 9 in decimal form. This means that there are combinations 1010 to 1111 to choose from to display a unit. 1101 was chosen for voltage, 1110 for current and 1111 for temperature.Figure Common