Components:
Center tapped step-down transformer 6V-0-6V
Bridge rectifier (DF02M) or 4 1N4001 diodes
2 2200µF, 25V capacitors
2 100nF ceramic capacitors
2 10µF, 25V capacitors
LM7806
LM7906
In my dual DC power supply, a center tapped transformer of 6V-0-6V is used. With the filter capacitor of 2200µF, the voltage entering the voltage regulator IC, LM7806 and LM7906 is approximately equals to peak voltage of the wave form minus 0.7 which is 7.8V; where 0.7 is the p-n junction voltage drop across the diode. That is
Vpeak - 0.7 = (Vrmsx√2)-0.7
(6x√2)-0.7 = 7.8
If you need dual DC power supply with voltage of 5V & -5V, 8V & -8V, 9V & -9V, 12V & -12V and so on, you will only change your transformer to the one with secondary voltage relative to what you want. Replace your voltage regulators with LM7805 & LM7905, LM7808 & LM7908, LM7809 & Lm7909, LM7812 & LM7912... accordingly. Also note that the capacitor must be replaced with the one that has voltage greater than the peak voltage.
|
|
|
