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university:courses:electronics:electronics-lab-32 [24 Jul 2017 16:11] – change amplitude value to peak-peak Antoniu Miclaus | university:courses:electronics:electronics-lab-32 [25 Jun 2020 22:07] (current) – external edit 127.0.0.1 | ||
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=====Hardware Setup:===== | =====Hardware Setup:===== | ||
- | AWG1 is connected as V< | + | AWG1 is connected as V< |
+ | |||
+ | {{ : | ||
+ | |||
+ | <WRAP centeralign> | ||
=====Procedure: | =====Procedure: | ||
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Start by using the large value 220 uF capacitor for C< | Start by using the large value 220 uF capacitor for C< | ||
- | Use the two scope inputs to monitor the input AC waveform at V< | + | Use the two scope inputs to monitor the input AC waveform at V< |
+ | |||
+ | {{ : | ||
+ | <WRAP centeralign> | ||
+ | {{ : | ||
+ | <WRAP centeralign> | ||
With scope channel 2 connected across shunt the 10Ω resistor R< | With scope channel 2 connected across shunt the 10Ω resistor R< | ||
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=====Questions: | =====Questions: | ||
- | Change the peak amplitude of the AC input waveform. What is the minimum peak value of the AC input where the PMOS transistor is still actively rectifying the input, i.e. the V< | + | Change the peak-to-peak amplitude of the AC input waveform. What is the minimum peak value of the AC input where the PMOS transistor is still actively rectifying the input, i.e. the V< |
Try different frequencies for the AC input. How does the frequency effect the peak value and the width of the current pulse in R< | Try different frequencies for the AC input. How does the frequency effect the peak value and the width of the current pulse in R< | ||
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There are other potential uses for a circuit that essentially allows current flow in only one direction with very low voltage drop across the switch. In battery chargers, where the input power source might be intermittent such as a solar panel or wind turbine generator, it is necessary to prevent the battery from discharging when the input power source is not generating a high enough voltage to charge the battery. Generally a simple Schottky diode is used for this purpose but as was pointed out in the background section this can lead to losses in efficiency. If an op amp with sufficiently low operating supply current is employed this can often be lower than the reverse leakage current in a large Schottky diode. | There are other potential uses for a circuit that essentially allows current flow in only one direction with very low voltage drop across the switch. In battery chargers, where the input power source might be intermittent such as a solar panel or wind turbine generator, it is necessary to prevent the battery from discharging when the input power source is not generating a high enough voltage to charge the battery. Generally a simple Schottky diode is used for this purpose but as was pointed out in the background section this can lead to losses in efficiency. If an op amp with sufficiently low operating supply current is employed this can often be lower than the reverse leakage current in a large Schottky diode. | ||
+ | |||
+ | <WRAP round download> | ||
+ | **Resources: | ||
+ | * Fritzing files: [[downgit> | ||
+ | * LTspice files: [[downgit> | ||
+ | </ | ||
**For Further Reading:** | **For Further Reading:** |