12v car battery chargers

i had an interesting experience tonight, i normally don't give it a 2nd thought clipping the clips to the battery terminals.. but i was not sure if it was even working so while holding the clip/+terminal of the battery i 'brush' the other clip and if it's working you'll see a load of sparks...

the sparks looked pretty and i was bored so i repeatdly did this 2 or 3 times and i noticed a muscle/nerve twitch i thought i was dreaming so i did it again ouu! so i stopped..

all i can think of, when the sparks take place, is it possible that the sparks are able to penetrate skin and contract muscles? the clip was metal with my hand firmly gripped ... but 14.5v does nothing until you create the sparks... what's going on any theories? :)

yes that is not safe. you are completing the circuit with no devices or resistance in between. By grabbing onto a stream of current, you may become apart of the circuit and when the electricity passes thru your heart you'll be dead. Respect Electricity! :astonished:

If your charger is a really cheap one its open circuit voltage could be in the order of 24 volts or so which is adequate to tickle you. Alternatively there may (unlikely though) be a smoothing inductor in the DC line which is providing a back-emf kick when you break the charge current.

But to get a tickle you need a return path, so it begs the question "what part of your body was in contact with the other pole of the battery or charger". If none, then put the charger in a place where it may never be used again !!

Right.. It's most-likely an inductor. Inductors "try" to keep the currrent through them constant. (Capacitors "try" to keep voltage across them constant.) When you break the circuit, the magnetic field around the inductor collapses and that keeps current flowing (for a short period of time, depending on the inductance). If you suddenly have infinite resistance, infinite voltage is required to mantain the current. Of course you can't get infinite voltage, but the voltage can spike high enough to break-down the air molecules (which means you no longer have infinite resistance) and you get a spark. It's the same way your ignition coil sends high-voltage to the spark plugs.

Or, if you have a high resistance (such as the resistance through your body) you can get dangerous voltages (and dangerous current) through your body.