Waveclipper with capacitors as Voltage sources.

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Discussion Overview

The discussion revolves around designing a circuit to clip a triangular waveform generated at 1kHz, with specific peak voltage requirements. Participants explore various circuit configurations using diodes, capacitors, and resistors, while addressing the challenges of achieving the desired clipping voltage.

Discussion Character

  • Homework-related
  • Technical explanation
  • Debate/contested

Main Points Raised

  • The original poster (OP) presents a circuit design but expresses uncertainty about the calculations needed for implementation.
  • One participant critiques the OP's use of capacitors, stating they can only charge and not discharge, suggesting that this would prevent clipping.
  • Another participant points out that without capacitors, the clipping would occur at approximately 0.7V instead of the desired 5V, proposing the use of voltage dividers to achieve the necessary clipping levels.
  • Concerns are raised about the power requirements of a low-resistance voltage divider needed for the proposed solution.
  • Participants suggest exploring the use of multiple diodes to achieve the clipping effect, with one proposing to treat the diodes like zeners with current-limiting resistors.
  • There is mention of a potential temperature-related issue affecting the voltage drop across the diodes.
  • One participant suggests a configuration involving two diodes, four resistors, and two capacitors, indicating a different approach to the problem.

Areas of Agreement / Disagreement

Participants express differing views on the use of capacitors and diodes in the circuit design. There is no consensus on the best approach to achieve the desired clipping voltage, and multiple competing ideas are presented.

Contextual Notes

Participants note limitations regarding the power requirements of proposed solutions and the potential impact of temperature on diode performance. The discussion does not resolve these technical challenges.

Who May Find This Useful

Students and hobbyists interested in circuit design, particularly those working on waveform clipping and electronics projects.

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Homework Statement




A triangular wave generator produces a waveform oscillating at 1kHz. Draw a circuit that will clip the waveform, with peak values now at 5V. You may use a DC power supply witou outputs of +10 V & -10V as well as resistors, capacitors and standard signal diodes. Indicate the components used and their respective values.


Homework Equations



v=iR
i=C*dv/dt
V_c=V_o(1-e^-t/RC)


The Attempt at a Solution



Okay guys, I designed the circuit successfully enough, here's a picture of it:

http://imageshack.us/a/img209/4081/circuit1.png


The problem is that I have almost no idea where to get started with the actual calculations. We had a very poor electronics teacher last year so I'm essentially playing catch up this year. Any help as where to get started would be greatly appreciated!
 
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Your circuit has serious problems. The capacitors can only charge, not discharge, so they and the diodes will look like open circuits and there will be no clipping. Vout = Vin.

Why are you thinking of using capacitors?
 
and without the capacitors it will clip at about Vf = 0.7V not 5V.

How about setting up a pair of voltage dividers with a voltage of + and - 4.3V. Then if the signal voltage exceeds 4.3+Vf or -4.3-Vf it will be clipped.
 
CWatters said:
and without the capacitors it will clip at about Vf = 0.7V not 5V.

How about setting up a pair of voltage dividers with a voltage of + and - 4.3V. Then if the signal voltage exceeds 4.3+Vf or -4.3-Vf it will be clipped.

He'd need a very low-resistance voltage divider, requiring oodles of power from the 15V supplies.

Is there a way around that?
 
Consider that the problem doesn't appear to limit you to using just two diodes...
 
gneill said:
Consider that the problem doesn't appear to limit you to using just two diodes...

You're thinking lotsa diodes from + and - supplies? :rolleyes:
 
rude man said:
You're thinking lotsa diodes from + and - supplies? :rolleyes:

Not quite. Lotsa diodes across the signal. No supplies. Treat each stack like a zener, so use a current limiting/voltage dropping resistor.
 
gneill said:
Not quite. Lotsa diodes across the signal. No supplies. Treat each stack like a zener, so use a current limiting/voltage dropping resistor.

Good shot. The resistor already exists. Hope it's not too small ... but if it is, the only alternative is an active circuit which the OP is not allowed ...

Of course, there is also the dVD/dT problem of -2n mV/deg C where n = no. of diodes ...
 
I'd use 2 diodes, 4 resistors and 2 capacitors ...
 

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