R
Rodo
Guest
Hi all,
I bought a transformer (Signal Transformer model st-6-48, 24VAC@0.8A,
parallel connection). I needed 24vdc to drive the coil of a relay. I thought
24vac after rectification and filter it should go to 30vdc so a 24vdc (7824)
regulator should be right. Well... the voltage at the input of the regulator
is 37vdc. It gets so hot you could fry an egg on it. I'm only drawing like
100mA. So ... I think (37-24)/0.100=1.3w is too much for a to-220 with no
heat sink ? and the more important question I have is how do you find the DC
voltage after rectification and filter when you are not drawing the full 0.8
amps ?
Thanks
I bought a transformer (Signal Transformer model st-6-48, 24VAC@0.8A,
parallel connection). I needed 24vdc to drive the coil of a relay. I thought
24vac after rectification and filter it should go to 30vdc so a 24vdc (7824)
regulator should be right. Well... the voltage at the input of the regulator
is 37vdc. It gets so hot you could fry an egg on it. I'm only drawing like
100mA. So ... I think (37-24)/0.100=1.3w is too much for a to-220 with no
heat sink ? and the more important question I have is how do you find the DC
voltage after rectification and filter when you are not drawing the full 0.8
amps ?
Thanks