2 INTRODUCTION Electronic Circuits The System Half-Wave Rectification Full-Wave RectificationRMS to AverageFiltersMultipliersRipple and RegulationZener Regulator
3 Electronic CircuitsPower SupplyCircuit ACircuit BCircuit CThe power supply energizes the other circuits in a system.Thus, a power supply defect will affect the other circuits.
4 Electronic Circuits Most line operated supplies change ac to dc. dc Power SupplyCircuit ACircuit BCircuit CdcdcacdcMost line operated supplies change ac to dc.
5 the positive end of the load. Electronic CircuitsThe cathode makes thisthe positive end of the load.+Half-wave pulsating dc+ac--A series rectifier diode changes ac to dc.
6 the positive end of the load. Electronic CircuitsThe cathodes make thisthe positive end of the load.+Full-wave pulsating dc+-ac-Two diodes and a transformer provide full-wave rectification.
7 Electronic Circuits VLOAD is equal to one-half the total secondary Only half of the transformer secondary conducts at a time.VLOAD is equalto one-half thetotal secondaryvoltage.C.T.VTOTAL½ VTOTAL
8 Electronic Circuits++ac-Full-wavepulsating dc-The bridge circuit eliminates the need for a transformer.
9 Reversing the diodes produces a negative power supply. Electronic Circuits++acFull-wavepulsating dc--Reversing the diodes produces a negative power supply.
10 Electronic Circuits Power Supply Review dc half full four cathodes Most line-operated power supplies change ac to ________.dcA single diode achieves ________ -wave rectification.halfTwo diodes and a center-tapped transformerprovide ________ -wave rectification.fullA bridge rectifier uses ________ diodes.fourThe positive end of the load is the end in contact with the diode ________.cathodes
11 Vac Vdc Vac Vdc Vac Vdc Ignoring diode loss, the average dc is 45% of the ac input forhalf-wave.VacVdcacConverting rmsto average
12 Vac Vdc Vac Vdc Ignoring diode loss, the average dc is 90% of the ac input forfull-wave.acVacVdc
13 Three-phase rectification is used in commercial, industrial and vehicular applications.Full-wave, 3 f bridge3 f120 V60 HzVdc = x Vrms = 162 V0 V-200 V+200 V20 ms40 ms0 ms
14 Three-phase rectifier output 200160120Vdc = x Vrms = 162 VVolts804010203040Time in milliseconds
15 Review Electronic Circuits 45% half 90% 90% 135% The average dc voltage with half-wave isequal to ______ of the ac voltage.45%The effective ac voltage in a two-diode,full-wave rectifier is _______ ofthe secondary voltage.halfThe average dc voltage with a full-waverectifier is _________ of the effective ac voltage.90%The average dc voltage with a bridge rectifieris equal to ________ of the ac voltage.90%The average dc voltage with a 3 f bridge rectifier is equal to ________ of the ac voltage.135%
16 Electronic Circuits VP Filter Discharge capacitor + ac Charge - A relatively large filter capacitor will maintain theload voltage near the peak value of the waveform.+Chargeac-
17 Electronic Circuits VP Discharge time is less. + ac - -Full-wave is easier to filter since the dischargetime is shorter than it is for half-wave rectifiers.
18 Adding a filter capacitor increases the dc output VacVdcIgnoring diode lossand assuming a largefilter, the dc output isequal to the peak valuefor both half-wave andfull-wave.Adding a filter capacitorincreases the dc outputvoltage.VacVdcac
19 Vac Vdc Vac Vdc Ignoring diode loss and assuming a large filter, the dc output isequal to the peak valuefor both half-wave andfull-wave.acVacVdc
20 Vac Vdc Vac Full-wave doubler Vdc Ignoring diode loss and assuming large filters,the dc output is twice thepeak ac input.acVacVdcFull-wave doubler
21 Electronic Circuits Half-wave voltage doubler The charge on C1 adds to the ac line voltageand C2 is charged to twice the peak line value.C1 is charged.C1acHalf-wave voltage doubler
22 (Ignore diode loss and assume a light load for this quiz.) Electronic CircuitsReview(Ignore diode loss and assume a light load for this quiz.)The dc output in a well-filtered half-wavesupply is _____ of the ac input.141%The dc output in a well-filtered full-wavesupply is _____ of the ac input.141%The dc output in a well-filtered half-wavedoubler is _____ of the ac input.282%The dc output in a well-filtered full-wavedoubler is _____ of the ac input.282%
23 Electronic Circuits Vac Vdc An ideal dc power supply has no ac ripple.
24 Electronic Circuits Vac Vdc 1.32 Vac 12 Vdc Vac Vdc ac x 100% ac ripple =x 100%= 11 %Real power supplieshave some ac ripple.VacVdc
25 Electronic CircuitsAn ideal power supply has perfect voltage regulation.The voltagedoes not change.VacVdc
26 Electronic Circuits Vac Vdc Vac Vdc DV x 100 % Voltage Regulation = VFL=12 V1 Vx 100 %VacVdcac= %The output of areal supply dropsunder load.VacVdc
27 The voltage across a conducting zener is relatively constant. Electronic CircuitsReverse Bias in Volts121086425I10ReverseCurrentin mA15Vrev20253035The voltage across a conductingzener is relatively constant.V
28 be used to regulate voltage. VacVdcIf the zener stops conducting, the regulation is lost.VacVdcElectronic CircuitsVacA shunt zener diode canbe used to regulate voltage.Vdcac
29 Review Electronic Circuits 0% 0% small small zener The voltage regulation of an ideal powersupply is ___________.0%The ac ripple output of an ideal powersupply is ___________.0%V in a real power supply should beas ___________ as is feasible.smallThe ac component of an ideal dc power supply should be as ________ as is feasible.smallA device that is commonly used to regulatevoltage is the ________ diode.zener