RC circuit- transient voltage

[unlv007]

A voltage source produces a DC voltage but this voltage has a lot of high frequency fluctuating voltage spikes. To ensure that there are no rapid transients, an RC circuit consisting of 10 ohmresistor and 1 microfarad capacitor is connected. It is said that RC time constant helps to clean the voltage. please explain more in detail.

 

[crutschow]

It's the combination of the resistor in series with the capacitor and capacitor to ground that reduces the noise spikes. It acts like a filter.

The time constant, which is R x C, simply is a measure of the frequency response of the filter. This is typically defined at the point where the filter response is -3dB (0.7) of the DC response. This frequency in Hz is 1/(2*Pi*R*C). As the frequency gets higher the filter absorbs more of the noise with the attenuation increasing at 6dB per octave of frequency increase, since the capacitor impedance goes down with an increase in frequency.

I don't know if the above makes any sense to you but if you want to learn more I'm sure a Google search will turn up numerous articles on circuits and filters.

 

[unlv007]

thanks for your response. My voltage source usually produces a clean DC but occasionally produces high frequency transient voltage spikes superimposed on dc. Now suppose i built an RC circuit and i want to test it. I have a good voltage source, how do i build a voltage source which will simulate the abnormal behavior?

 

[crutschow]

If you know the frequency and voltage characteristics of the noise, than you can input a similar signal from a signal generator.

The best way is just to test with the noisy source.