Discussion in 'General Electronics Chat' started by worldHello, Oct 18, 2014.

1. ### worldHello Thread Starter New Member

Oct 15, 2014
23
0
Hello, all:

So I have to deal with transformers for my project. From my understanding, a typical transformer one sees in a textbook has two parameters N1 and N2. The relation between Vin and Vout is then Vout = (N1/N2 ) Vin. In other words, N1:N2 is the ratio. If N1 < N2, then it is a step down transformer.

However, most transformers one can buy have rating of Vin and Vout with specific numbers. For example, Vin = 12 V and Vout = 6 V. I do not understand how this works. If I input a 9-volt voltage to this transformer, what would happen? Does it have to take 12 V as its input?

Thank you.

2. ### MrChips Moderator

Oct 2, 2009
14,242
4,174
12V:6V means that the turns ratio is 2:1.

Hence 9V in would give you 4.5V out.

3. ### crutschow Expert

Mar 14, 2008
16,179
4,322
But you can't generally put more voltage at the input then its rated voltage at the rated frequency or the transformer core can saturate with subsequent high input current.

4. ### t_n_k AAC Fanatic!

Mar 6, 2009
5,448
784
N1 presumably states the primary winding turns and N2 the secondary winding turns.
Surely if N1 < N2 (or N2 > N1) then one has a step up transformer .....