# Is there any electronic component that allows video signal to pass and stop current from passing?

valentin68 | College Teacher | (Level 3) Associate Educator

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Yes there is such a component. Its name is a capacitor. Explanation follows.

A video signal is different from a usual current in what it concerns its frequency. Video signals are alternating currents with frequencies in the range 0-6.5 MHz while normal power supply  currents are DC or household AC meaning their frequency is either zero or 60 HZ (50 Hz). When you connect a capacitor in series in a circuit containing both these signals, because the capacitor reactance (or in other words its complex resistance) decreases with signal frequency

`X_c = 1/(omega*C) =1/(2*pi*F*C)`

Thus for the usual video frequencies (1-6.5 MHz) the series reactance will be small enough while for normal power supply currents it will be very high (tend to infinity). Therefore it will separate the video frequencies from the normal power supply currents.

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