Don’t Take Capacitors for Granted

Capacitors are some of the simplest and easiest components to use…

… until you plug them in backwards!

Basically, a capacitor is like a gas tank that can be filled with charge or electrons. In case of a gas tank you apply pressure to the air to force it into the tank, and if you try to remove the pressure, the gas tank will force the air out creating pressure and therefore there is a resistance towards the change of pressure.

Similarly, the electrons are forced into the capacitor by applying voltage and if you try to change the voltage, the capacitor will force its own voltage out and therefore there is a resistance towards the change of voltage. That’s why capacitors are mainly used in filtering circuits as well as to store energy.

There are many different types of capacitors. Many of them have polarity, like tantalum and electrolytic capacitors, and many don’t have polarity like ceramic capacitors.

The polarity means that one must make sure that the capacitor is correctly connected such that the voltage on the positive pin of the capacitor is always higher than the negative pin. Or else, you saw what happened in the video!

The capacitor in the video was an electrolytic capacitor. This type tends to explode. Because when used wrongly, the capacitor heats up and the material inside the case vaporises and the pressure builds inside the case, big enough to explode. On top of the case of newer and usually larger capacitors they often create grooves so that if the pressure builds inside the case for any reason, the grooves crack and let the pressure out to avoid explosion.

Tantalum capacitors on the other hand burst into some wild flames. So in either case, be careful!

16 thoughts on “Don’t Take Capacitors for Granted

  1. Hi Mehdi S.

    I have a transformer to step up the voltage , i came to know when i blew up my multimeter , if i put wire too close (just seems to touch) it create sparks but i need to incresce the lenght of arcs but the capacitor and inductor parallel oscillator in primary coil doesn’t sewms to work please help , and bdw i have chosen article wilth less comments, thanks for your help

  2. Hi, my 15 yo son showed my your videos today. I immediately loved them like he does- we saw the guitar vid first, hilarious. You did a terrific job in getting him interested in engineering & electricity.

    One minor comment to the exploding electrolytic capacitor: AFAIK, it does not explode because it heats up. Its made of aluminum and citric acid in water. They are separated by a thin layer of aluminum oxide. Connected properly, the layer will increase. If you do it wrong, the layer will decrase, and finally the water will decompose, gas builds up pressure and the thing goes kabloom. I did this myself, and I guess I will have to show my son now …

  3. sir can i ask for the schematic of your blinker? I’m working on my past projects and i used 2 led lights to create a flipflop but when i transpose it into a blinker i can’t make it function… can you help me???

  4. Mehdi, could we get the schematic for the circuit? I am a student and have been able to create blinker without using the 555 timer so I would really appreciate if you could explain this circuit.

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