I am confused and keep seeing the term "decoupled capacitor" tossed around. How are these capcitor used in circuits? Does it remove DC?

I asked becaused, I have a circuit with 10nf capacitor and 100ohms in series with each other connected to the gate of a silicon controlled rectifier (SCR). I want to know the purpose of this. The AC sine wave is inputted into the circuit.

Any help would be great.

 

Could someone post a diagram of a simple circuit using a decoupling capacitor(s) with a detailed explanation of how it/ they work in the circuit?

 

Thats an RC Snubber network your seeing on the gate of the SCR. It's used for transient protection. See the application note on the link from Fairchild semiconductor.


RC Snubber Networks - Application Note

 

Originally posted by JoeJester@Jul 15 2005, 10:55 PM
As the audio amplifier circuits illustrated below operates normally, the current in the collector changes. This changing current represents a changing load to the power supply, pulling more or less than the quiesent current.

As we add more circuits, these varying loads can affect the voltage felt at the respective collectors. So, in order to reduce this variance, we decouple the output variances to present a more stable load to the power supply. Look at the signal called I ps, this represents the current variances in the circuit close to the power supply. In the circuit without decoupling, the variance is about 750 uA around the quiesent current. With the decouping, we reduced that variance to about 12 uA about the quiesent current. The output remained normal.

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Why was the 100 ohms resistor added?