Help with small transformer please

[milen007]

Hi guys

I need help with small toroidal tranformer with typical regulation of 35%.

I need 15v of this 7va toroidal. But the open circuit measured 20v

Is there anyway to bring down the voltage? When its underload, it only went down to 18v. How to make it went down to 15v? I cant load it with more.

Thanks in advance

Erwin

[VictoriaGuy]

Is the secondary wound on top of the primary? You could try unwinding some turns....

[milen007]

Hi viactoriaguy

Thanks for the respond forget to mention that its a pcb mounted type which is impossible hacking into the sealed case

Are putting resistors in series with the secondary output would help bring down? If possible. Whats the formula to calculate the resiators value?

Erwin

[mickeymoose]

Erwin: Show us your circuit? Most will be able to handle that 3v difference! E

[VictoriaGuy]

Originally Posted by mickeymoose

Erwin: Show us your circuit? Most will be able to handle that 3v difference! E

There's probably a regulator in the DC side of the circuit that should handle the extra voltage...you might need a bigger heat sink on the regulator if it needs to dissipate more energy.