help(design a DC power supply using an IC voltage regulator)

[shinn90]

i need to get output voltage of -5V. Is circuit correct?

Assume that there is negligible ripple voltage across C1.
VC1(pk) = VI = -10V
Vs(peak) = -10V -0.7V - 0.7V

Therefore the secondary voltage rating of the transformer (in rms):
Vs(rms) = -11.7V/1.414 = -8.27 volts

**broken link removed**

electrical characteristics
Cout= 1uF , cin =0.33uF , Iout= 350mA, Vin = -10V

 

[MrAl]

Hi,


You need more capacitance on the input. 3000uf should do it and get this
working down to low line too. The transformer secondary should be 10vrms,
or a little higher. It might work with a lower rms voltage too if the equivalent
series resistance of the secondary isnt too high.