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Since impedance is the vector sum of resistanceand reactance, and since reactance is a function of frequency, impedance only really applies to a.c. circuits. You could argue that, in a d.c. circuit, impedance is equal to resistance, but the term really isn't normally used in d.c.

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Is a capacitor used to change an AC voltage to a lower or higher value?

Yes.... capacitors offer impedance to flow of ac current.. But since the value of impedance is inversly proportional to the frequency of source therefore the impedance offered generally is much lesser than in case of dc current


Why do not you use impedance in DC circuit?

Actually, its a matter of terminology... Impedance can be used in a DC circuit. We just call it resistance, however, transient analysis would imply a different notation. To be clear, impedance is normally used in AC circuits, and it is the electrical opposition to AC, taking into account not only voltage, but phase angle. In a DC circuit, impedance and resistance are the same thing, simply with a phase angle of zero.


Volts peak is equals to dc volts?

"Voltage peak" is generally used to denote the maximum(amplitude) of AC voltage supply. It can not be approximated as dc value. The closest approximation one can make for dc value of a ac supply is the RMS(root mean square) value of the voltage. So that the ohmic loss caused by the given AC voltage supply is equivalent to that caused by a dc supply having value equal to the RMS of this AC supply (for given impedance & time).


Will value of J be same if ac were used instead of dc?

The number of Joules (energy) is the same as dc provided the RMS values of the ac quantities are used.


How do you change dc values to ac values?

To convert DC values to AC values if you are wanting RMS values they are the same. 100V DC and 100V AC (RMS) are the same "value". If you want to know the Peak-To-Peak AC value you would multiply the RMS value by 1.414. So 100V AC RMS equals 141.4 V Peak to Peak.


What is purpose of emmiter bypass capacitor in R-C coupled amplifier?

Emitter bypass capacitor is a capacitor which provide low impedance to AC and high impedance to DC . AC is shunt then only DC appears on RC and volage gain increses.


What is electrical impedence?

Electrical impedance is the total opposition to current flow. It includes both a resistive, or DC component and a reactive, or frequency-dependant component. Impedance is the same as resistance if the applied voltage is DC. For AC voltage, the reactive components opposition to current flow changes with frequency, so impedance is typically specified at a particular frequency.


Is impedance and resistance are different?

Resistance is a concept used for DC (direct currents) whereas impedance is the AC (alternating current) equivalent. Impedance is a more general term for resistance that also includes reactance.


What is the opposition to the current flow?

resistance is the opposition to the flow of electric charge


What is the difference between ac and dc grounding?

The difference AC and DC grounding is that AC is alternate current and DC is direct current. Grounding for both AC and DC is the same.


Will 30 volts of supplied AC voltage produce the same current as 30v of DC through 2 kilo ohm resistance?

Yes. Because the 30v ac is root-mean square value which is the value of an alternating quantity that will produce the same heating effect as the DC quantity when applied to the same resistance.


What is ac and DC resistance of a diode?

diodes follow an exponential curve meaning non linear in nature. by using Boltzmann formula an impedance can be calculated. That would be the AC Resistance the dc resistance on any device is the voltage drop divided by the dc current.