Capacitor Tutorial – Symbol, parameters, connections

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Capacitor

capacitor

Capacitor – a fundamental passive electronic component (next to Inductor and Resistor), which is made of at least two electrical conductors (plates) and a dielectric separating them (the insulator).  After applying voltage to the plates, the gathering of the electric charge begins.
Depending on the matter of construction, parameters and the type of system in which capacitors were applied they can collect energy, engage (energy transfer), filter and block the signals. Filters and RC timers took its name from the combination of Resistor and Capacitor in one single system – and similarly in the RLC system Resistor and Capacitor were used but with the addition of the Coil.

capacitor symbol

Capacitor Symbol

 

The capacity of a capacitor (the amount of charge that capacitor can store) is expressed in Farad [F]. Despite the fact that 1 Farad is a large unit, the commonly produced capacitors are with capacitance values of pico [pF], nano [nF] and micro [µF]

capacity of a capacitor

C – capacitance of the capacitor [FFarad]
Q – electric charge on one plate [CCoulumb]
U – the voltage between plates [VVolt]

The main parameters of capacitor:

  • Rated capacity – the value provided by the manufacturer, it determines the capacity of this element,
  • Capacitance tolerance – it’s given in percentage [%], the maximum deviation of the actual value of the item from its nominal value,
  • Rated voltage – the maximum voltage of the element work, it’s generally given as the sum of the voltage and the peak value of the alternating voltage,
  • Test voltage – the voltage that the capacitor is able to “withstand” in a short time,
  • Temperature coefficient of capacitance (TCC)- it describes the maximum change in capacitance in the given range of temperatures,
  • Leakage – responsible for self-discharge of the capacitor, dependent on the insulation resistance,
  • Resistance to voltage pulses – described the optimal frequency of charging and discharging the capacitor,
  • Capacitor dissipation factor (tan δ) – it is dependent from the temperature and frequency, the higher value, the worse quality of the capacitor.

Connecting of the capacitors:

As it is in case of both inductors and resistors, capacitors can be connected in parallel and in series.
Series connection:

Capacitors connected in series

Capacitors connected in series

Capacity of capacitors connected in series (unlike the resistors) can be described by the following formula:

Capacitors connected in series
Parallel connection:

 

capacitor Parallel connection

Capacitor Parallel Connection

Capacitance of capacitors connected in parallel are given by the formula:

capacitors connected in parallel

The electric charge of capacitors connected in parallel are the sum of the charges gathered on them – as the relation above indicates.

Popular types of capacitors:

  • electrolytic – they work only at low frequencies, have considerable capacity and the amount of leakage,
  • ceramic – usually operate at high frequencies, trimmers, which are variable-capacitance capacitors, are also made of this material,
  • polymer – (plastic) – they are suitable for the operation at high currents and characterized by high voltage resistance.
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I'm Michael. Me and my friend John are students of electronics. We are creating this site to help students and any interested people understand electronics.

6 thoughts on “Capacitor Tutorial – Symbol, parameters, connections

  1. I’m not sure where you are getting your info, but great topic.
    I needs to spend some time learning more or understanding more.
    Thanks for excellent info I was looking for this
    info for my mission.

  2. Also we remember from the last tutorial that with a polarised electrolytic capacitor, the positive lead must go to the positive connection and the negative lead to the negative connection otherwise it may again become damaged.

  3. I must thank you for the efforts you’ve put in writing this blog.

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  4. Capacitors that have both of their respective terminals connected to each terminal of another capacitor are said to be connected in Parallel.

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