I have bought a shocking gum which gives a small electric shock when you pull a side, like this one : http://img.weiku.com/waterpicture/2011/10/31/20/Shock_Chewing_Gum_634577515693532881_3.jpg

I wanted to know how it works so i opened it and there are two components i can't identify.

Here is the picture :

enter image description here

It's the black component (maybe a capacitor ?) and the little circular one I can't identiy. Any ideas ?

  • \$\begingroup\$ The big black one is an inductor. What circular one are you on about? \$\endgroup\$
    – Majenko
    Dec 1, 2014 at 14:27
  • \$\begingroup\$ The big black one might be a transformer - note the middle leg? It's def a wound component though - try Murata or Bourns. \$\endgroup\$
    – Andy aka
    Dec 1, 2014 at 14:48
  • \$\begingroup\$ The circular component I'm talking about is the one below the black one, but I'm not sure if it's a component or just a small circuit board part. \$\endgroup\$ Dec 1, 2014 at 15:00
  • \$\begingroup\$ @Arizer59300 That would be a very strange shape for a PCB- unnecessarily expensive. Also the color and silver plating are wrong for a device that should cost pennies to make. \$\endgroup\$ Dec 1, 2014 at 15:06

2 Answers 2


If you mean that round white thing- that's an interesting question. I'm guessing it might be an ultrasonic (or maybe high frequency sonic) piezo element that resonates with the black cylindrical drum-wound autotransformer or inductor or tapped inductor (some inductors have an extra leg for support that is non-functional electrically).

The inductor looks like a ferrite bobbin wound with wire, but it's got a length of black shrink-wrap tubing over it to protect the windings.

Here's a typical inductor of this type: http://www.globalmarket.com/product-info/dip-ferrite-core-inductor-drum-core-inductor-3853750.html

Then you'd only need perhaps a single cheap transistor and maybe a resistor to generate the 'joke' electrical shocks.

  • \$\begingroup\$ It looks like this indeed. So when the circuit is closed (by pulling the fake gum), the current passes through the piezo element and the inductor, which generates the electroshock right ? But does the inductor behave like a tranformer ? Because if not how can small three button cells gives you an unpleasent electro shock ? \$\endgroup\$ Dec 1, 2014 at 15:28
  • \$\begingroup\$ @Arizer59300 Resonance can generate very high voltages at a specific frequency (if the circuit has high 'Q' and is driven right at resonance). We used a similar self-resonant circuit commercially to for a high voltage drive to create virtually painful sound levels for alarm annunciators. \$\endgroup\$ Dec 1, 2014 at 15:39

The black cylindrical thing at top is some sort of inductive component. Since it seems to have 3 pins, it is probably a small auto-transformer. That would also make sense considering this device is apparently meant to produce short high-voltage pulses.

The silvery circular thing under the clip is most likely the battery.


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