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How to convert ohms to microfarads

Science 2021

A capacitor is an electrical component that stores energy in an electrical field. The device consists of two metal plates which are separated by a dielectric or an Iolator.


A capacitor is an electrical component that stores energy in an electric field. The device consists of two metal plates separated by a dielectric or an insulator. When a DC voltage is applied to the terminals, the capacitor draws current and continues to charge until the voltage on the terminals matches the supply. In an AC circuit in which the applied voltage changes continuously, the capacitor is continuously charged or discharged at a rate that depends on the supply frequency.

Capacitors are often used to filter out the DC component in a signal. At very low frequencies the capacitor behaves more like an open circuit, while at high frequencies the device behaves like a closed circuit. As the capacitor charges and discharges, the current is limited by internal impedance, a form of electrical resistance. This internal impedance is called capacitive reactance and is measured in ohms.

What is the value of 1 farad?

The farad (F) is the SI unit of electrical capacitance and measures the ability of the components to store charge. A one-farad capacitor stores a coulomb charge with a potential difference of one volt across its terminals. The capacity can be calculated from the formula

C = Q / V

Where C. is the capacitance in farads (F), Q. is the charge in coulombs (C) and V. is the potential difference in volts (V).

A farad-sized capacitor is quite large because it can store a lot of charge. Most electrical circuits don't need that large capacitance, which is why most of the capacitors sold are much smaller, typically in the pico, nano, and microfarad ranges.

The mF to μF calculator

Converting millifarads to microfarads is a simple process. You can use an online calculator for mF to μF or download a capacitor conversion as a PDF. However, a math solution is simple. One millifarad is equal to 10-3 Farad and a microfarad is 10-6 Farads. Convert this will

1 mF = 1 × 10-3 F = 1 × (10-3/10-6) μF = 1 × 103 μF

You can convert picofarads to microfarads in the same way.

Capacitive reactivity: The resistance of a capacitor

As a capacitor charges, the current through it drops rapidly and exponentially to zero until its plates are fully charged. At low frequencies, the capacitor has more time to charge and pass less current, resulting in less current flow at low frequencies. At higher frequencies, the capacitor spends less time charging and discharging and accumulates less charge between its plates. This causes more current to flow through the device.

This "resistance" to the flow of current is similar to a resistance, but the key difference is that the current resistance of the capacitor - the capacitive reactance - varies with the applied frequency. As the applied frequency increases, the reactance, which is measured in ohms (Ω), decreases.

Capacitive reactance (Xc) is calculated using the following formula

Xc = 1 / (2πfC)

Where Xc is the capacitive reactance in ohms, f is the frequency in Hertz (Hz) and C. is the capacity in farads (F).

Capacitive reactance calculation

Calculate the capacitive reactance of a 420 nF capacitor at a frequency of 1 kHz

Xc = 1 / (2π × 1000 × 420 × 10-9) = 378.9 Ω

At 10 kHz the reactance of the capacitors becomes

Xc = 1 / (2π × 10000 × 420 × 10-9) = 37.9 Ω

It can be seen that the reactance of a capacitor decreases as the applied frequency increases. In this case the frequency increases by a factor of 10 and the reactance decreases by a similar amount.

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