Experiment # 7 EE 312 Basic Electronics Instrumentation Laboratory Wednesday, October 25, 2000 InputFilterRegulationLoad

Objective: Design, construct, and test a dc power supply. The power supply includes a transformer, diodes, and a filter. All were investigated in previous experiments. This the major design project in the course.

Transformer FilterRegulator Alternator or Power Company Rectifier Load t v Input: 120 VAC RMS, 60 Hz Steps the input voltage up and down as needed Convert the ac to a pulsing dc Low-pass type for removing voltage variation Keeps voltage constant regardless of load change DC-VOLTAGE POWER SUPPLY OPERATION

Transformer FilterRegulatorRectifier Load Power Company t v V rms 16.7 ms or 60Hz

Transformer FilterRegulatorRectifier Load Alternator or Power Company t v V rms 16.7 ms or 60Hz t v V rms 16.7 ms or 60Hz

Transformer FilterRegulatorRectifier Load Alternator or Power Company t v R Load t v half-wave rectifier full-wave rectifier 60Hz 120Hz

Transformer FilterRegulatorRectifier Load Alternator or Power Company t v V rms 16.7 ms or 60Hz ~ 0.6V t v half-wave rectifier Hz V rms t

Transformer FilterRegulatorRectifier Load Alternator or Power Company InputFilterRegulationLoad stage 1 stage 2

t v t t v t V max ripple InputFilterRegulationLoad stage 1 without C with C C

t v V max ripple t V DC 0 ? ?

stage 2 One or more filter sections are usually used to reduce the amplitude of the ripple. The filter used in this experiment is a single-section low-pass RC filter. InputFilterRegulationLoad C R V input

Transformer FilterRegulatorRectifier Load Alternator or Power Company We design and built a 12 V dc regulated power supply. In this experiment you use a Zener diode that breaks down at 12 V.

IDID VDVD Forward Characteristics Reverse Characteristics 12Volts breakdown voltage ~ ~ I Max IzIz I Load I DC IzIz

IDID VDVD ~ ~ I Max R Load Rs RzRz I DC I Load IzIz R Load Rs RzRz I DC I Load IzIz Voltage Divider = V input

Transformer FilterRegulator Alternator or Power Company Rectifier Load t v Summary

Procedures: I- Design, construct, and test a dc power supply. Week 1 II- Simulate dc power supply. Week 2

Components: 18 Volts Transformer Variac Bridge rectifier (use 1 diode) Zener diode (Vbd=12Vdc, 1N4742) 12 Watt, 1000 Ohm, variable resistor 2 Resistor Substitution Boxes 50, 100, and 200  F Fixed Capacitors

1- Design, construct, test a dc power supply V Load =12 V dc I Load = ? Peak to peak ripple voltage from the input stage = ? Peak to peak ripple voltage at the load = ? R? C? R? C?

t v V max = 24.9 ripple t V DC =22.4 V 0 20% ripple V min =19.92

2- Simulation of Part I Simulate the dc power supply! Show output wave form at points 1, 2, and 3. Comnpare these waveforms with your experiment. 123

V Load =12 V dc R F =100 Rs=100 C F=100uF C I =250uF Iz=10.5mA ? Variac Transformer 18.0 V Vvariable

Report is required Electronic & Paper Before 1 PM Tuesday Nov. 21