A capacitor impedance is effected by frequency; the capacitor can be modelled as: 1/(j*w*C), j = i = imaginary number, w = omega (frequency in radians), C = capacitance in Farads.
To understand filtering, you must look at the output vs. the input relationship - Vo/Vi.
If you have a capacitor in SERIES with a resistor, and your output is across the capacitor, this boils down to a simple voltage divider:
Vo = Vi*1/(j*w*C) / (R + 1/(j*w*C)) = Vi * 1 / ((j*w*C) + 1)
Therefore, Vo / Vi = 1 / ((j*w*C) + 1)
So you can see as the frequency increases (w increases), Vo will become smaller and smaller - thus this is a lowpass filter. Similarly, if the output is taken across the resistor you will find this is a high pass filter.
I'm not sure what you're meaning by connected in parallel. If I have misunderstood your question, please post an update to the answer or comment in the discussion area.
it is the circuit that is responsible for producing oscillation.In hartley it is two inductors connected in series and a capacitor parallel to this series connection.Without tank oscillator tends to act as as an amplifier.
Because the ammeter connected in parallel will act as a short circuit.
A transistor acts like a resistor when Gate is connected to Source.
If they were in series in the circuit, they would act as on/off switches.
is it ? are you sure ? but i know so many circuit where capacitor is connected with ac supply . still , if u connected a capacitor to dc supply , then : 1. if it is in SERIES with the dc supply , it will block all the dc current as capacitor provides infinite resistance to dc current . application : where u want to block dc current.(simple high pass filter) 2. if it is in PARALLEL with the dc supply , it will not block dc current , but if any ac current comes out from the supply , the ac current will go through the capacitor , as capacitor provides small resistance to ac current. application : a) where u want to block ac current.(simple low pass filter) b) to filter the noise (ac components) of dc supply.
The conductors of the transmission line act as a parallel plate of the capacitor and the air is just like the dielectric medium between them.A capacitor is a device used to store electrical charge and electrical energy.
capacitor acts as resistor because it has some resistace alos.
Parallel
The main difference is that lighting caps are required to contain a bleed resistor in parallel across the cap s terminals to drain the high voltage contained in the capacitor to safe levels (usually within a minute or so) after the equipment is switched off. Motor run caps don't require bleed resistors due to them being constantly connected to the motor windings which act like a resistor to drain the capacitor after use.
reverse bias it
Well firstly, is the capacitor connected to a DC or AC supply. On a DC supply the capacitor would draw current until it had fully charged, at which point the current falls to the leakage current. Electrolytic capacitor will always leak a little. On an AC connection, current will pass continuously, and the capacitor may rupture if connected across an AC supply. The current that would flow on an AC connection is given by the impedance, which is calculated from the reciprocal of 2 x Pi x F x C Because it is the reciprocal, the impedance reduces as the capacitance in Farads (F) increases. So, the bigger the capacitance, the higher the current. Therefore, for AC, only low values of capacitor are found connected across the supply (usually with a resistor in series) for interference snubbing across a contact or switch. Larger values are placed in series with the current, to act as current limiters or high pass filters.
The cutoff frequency of filter depends upon the value of capacitor and resistance. Therefore, below cutoff frequency or above this frequency, capacitor allow to pass all other frequencies.