# a M&G riddle for ye (1 Viewer)

#### klufs2003

##### jesus lol
well not really a riddle more of a question lol, in a transformer found in an ordinary science lab the voltage is stepped down to like 2 - 12V to make it safer for the kids but if u used a step down wouldnt that increase the current making it more dangerous??? if they wanted to make safe transformers wuldnt it b safer to step up the voltage??
thanks for the help
- Klufs2004

#### alcalder

There would also be other components in the lab power supplies. The current levels and voltage levels are both dropped to safer amounts. If you are interested more in how they work, why not ask your teacher or school lab technician if you can have a look at the user manual for the power supplies. Actually, that's not a bad idea for all Physics students.

But, yes, DO NOT go sticking your finger in the power supply at any rate . Even low currents and voltages, if they pass through the body in the wrong way, can cause damage.

#### bboundy

##### New Member
There are alot of resistors and zener diodes in those things as well. These pretty effectively lower both voltage and current.

#### helper

##### Active Member
most school lab power supplies are limited to 5A

#### twilight1412

##### Member
its official the only thing in a school lab concerning eletricity that can kill you besides sticking your hands in a power point is and induction coil 10000 V is dangerous no matter how lil current there is

#### bboundy

##### New Member
I beg to differ. A spark that can jump a gap of 1mm (such as when you zap a friend) is about 15 000V. An electric fence is about 20 000V.
ATry putting your hands on them at the lowest voltage you can give it, then slowly up it. It might hurt, but its not actually very dangerous.

#### thehootman

##### Member
Do you remember Ohms law?
Your body has a high internal resistence, thus requiring a high voltage to pass a high current thru you. That means that 12v generally is safe as the resistence of your body reduces the current to next to nothing.

The lab power supplies have electromagnetic circuit breakers that limit the current to 5A.

Nothing in the Phys lab can kill you, except if you beat someone to death with a rheostat.