Self-induced voltage?

Status
Not open for further replies.

EEC

Senior Member
Location
Maryland
I am I correct, self-induced voltage from inductance is 180 degrees out-of-phase with the applied voltage. Also that because of the self-induced voltage the current lags the voltage 90 degrees.

Does this current lag take place through out the entire circuit or just through the inductor?

Another question I need answered is, does the current stay the same through out a series circuit with capacitors in the circuit? Even though current cannot flow through the capacitors.
 

G._S._Ohm

Senior Member
Location
DC area
I am I correct, self-induced voltage from inductance is 180 degrees out-of-phase with the applied voltage.

Does this current lag take place through out the entire circuit or just through the inductor?

does the current stay the same through out a series circuit with capacitors in the circuit? Even though current cannot flow through the capacitors.

That's because the inductor tries to maintain the current through itself, just like its dual, a capacitor, tries to maintain its terminal voltage.
If the top of the inductor is positive and has current flowing into it and you open a switch then the bottom of the inductor will become positive and source current into the rest of the circuit.

In an inductor in an AC circuit the current is 90 degrees from the voltage. In resistors the voltage and current are in phase. For a series AC circuit containing Rs, Ls and Cs you should probably use the current as the reference.

By definition the current is the same in all parts of a series circuit.
When there is a capacitor in a series AC circuit, the current that seems to flow through the cap is called displacement current [I think].
 
Last edited:

steve66

Senior Member
Location
Illinois
Occupation
Engineer
I agree with G.S, but I would add:

Yes, for a series circuit with an inductor, the current lags the voltage in all parts of the circuit. Remember, in a series circuit, the current is always the same in all parts of the circuit.
 

richxtlc

Senior Member
Location
Tampa Florida
I am I correct, self-induced voltage from inductance is 180 degrees out-of-phase with the applied voltage. Also that because of the self-induced voltage the current lags the voltage 90 degrees.

Does this current lag take place through out the entire circuit or just through the inductor?

Another question I need answered is, does the current stay the same through out a series circuit with capacitors in the circuit? Even though current cannot flow through the capacitors.

In an inductor, the magnetic field that is created opposes the current that created it, causing the current to lag the voltage. This is why an inductor placed is series is a current limiting device, it opposes any change in current.
The current will lag the voltage by some angle less than 90deg. due the the resistance in the circuit. (Pythagorean's Theorum).
 
Status
Not open for further replies.
Top