<^< Simple Power Supply | Course Index | Operational Amplifier Circuits >^>
| Objective:
| To investigate the operation of a simple regulated power supply.
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| Underpinning knowledge:
| Bridge rectifiers. Reservoir and smoothing circuits. Zener diodes.
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| Apparatus:
| TINA circuit file, or apparatus to make the following circuit.
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| TINA Circuit File:
| Click here to download circuit file
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| Initial Settings:
| Alternating current supply of 10V at 50Hz.
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| Requires:
| Paper, Linear graph paper, pen or pencil.
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| Instructions:
(a) Use the oscilloscope to display two or three cycles of the voltage waveforms developed across the reservoir capacitor (C1) and load (RL) using a common time scale.
(b) Sketch the waveforms in (a) and include labelled axes of voltage and time.
(c) Measure the output voltage produced by the power supply with RL = 100Ω, RL = 200Ω, and RL = 50Ω.
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Observations:
Comment on the shape of the waveforms and the output voltage produced by the power supply (this should be approximately the same as the nominal zener voltage). Comment on the effect of increasing the loading on power supply (i.e. reducing the value of RL so that more current is supplied) on the output voltage produced.
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| Further work:
Redesign the simple power supply so that it delivers a nominal 9V into a load of 90Ω (i.e. an output current of 100mA). The ripple voltage on the output should be no more than 100mV peak-peak at full-load. Justify all component values used in your modified circuit.
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<^< Simple Power Supply | Course index | Operational Amplifier Circuits >^>
