Memorandum

To: EE 222 Classmates

From: Shala M. Powell and David T. Strickland

RE: Nifty Diode Circuits Report

Date: November 6, 1995

Purpose

To explore the functions of an interesting circuit.

Experiment

We obtained circuit 2 from our lab instructor. We used a capacitor value of .22 microfarads, the 1N4007 diode, and we were required to use load resistances of 10 kiloohms and infinity (open circuit, no load) and an input signal of 1 kHz at a 4V (peak) sinusoidal voltage.

Analysis

We measured the input and output curves when the circuit had a load of 10 kiloohms. We determined this circuit to be a clamping circuit. This circuit only allows a system to operate in one direction. A descriptive name for this circuit could be "Clampi ng Circuit". We produced the plot on Scopelink to see what the output voltage looked like as a function of time. We could not produce a transfer function plot for this circuit because it was distorted due to the differences in fr equencies of the input and the output.

We also measured the input and output curves when the circuit had a load of 10 kilohm and the polarity of the diode was switched. We determined this circuit to work in reverse of a normal clamping circuit. This circuit would only allow a system to work in the opposite direction. A descriptive name for this circuit would be "Reverse Clamping Circuit". We produced a plot on Scopelink to see what the output voltage looked like as a function of time. We were not able to produce a transfer function plot because it was also distorted due to the differences in frequencies.

We measured the input and output curves when the circuit had an open ciruit (no load, infinity). We determined this circuit would produce nearly the same output voltage as the input voltage in the positive direction. A descriptive name for this circuit w ould be "Input equals Output". We produced a plot on Scopelink to see what the output voltage looked like as a function of time. We produced a transfer function plot for this circuit. We determined Vout /Vin to be ten.

We measured the input and output curves when the circuit had an open circuit (no load, infinity) and the polarity of the diode was switched. We determined this circuit would produce nearly the same output voltage as the input voltage but in the negative direction. A descriptive name for this circuit for this circuit would be "Input equals the negative Output". We produced a plot of Scopelink to see what the output voltage looked like as a function of time. We producted a transfer function plot for this circuit. We determined Vout/Vin to also be ten.

Conclusion

We conclude that this circuit is a clamping circuit. This circuit restricts the voltage to approximately the range of 0 to 6.3 V. This would be useful to use when you only want the circuit to work in the positive direction. For example, if you built an automobile motor, you would only want it to operate when the voltage is positive. By inserting this clamping circuit, you would be able to regulate the voltages.


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