Components:
12Volt Step-down transformer
Bridge rectifier (DF02M) or 4 1N4001 diodes
LM7812
2200µF, 35V capacitor
100nF ceramic capacitor
10µF, 35V capacitor
Bridge rectifier (DF02M) or 4 1N4001 diodes
LM7812
2200µF, 35V capacitor
100nF ceramic capacitor
10µF, 35V capacitor
In this circuit, transformer with 12V secondary voltage is used. With the filter capacitor of 2200µF, the voltage entering the voltage regulator IC is approximately equals to peak voltage of the wave form minus 1.4; where 1.4 is the p-n junction voltage drop across two diodes as each half cycle passes through two diodes. That is
Vpeak - 1.4 = (Vrms x √2) - 1.4
(12 x √2) - 1.4 = 15.6
hence filtered DC voltage applied to the input of LM7812 is 15.6V.
If you need output voltage of 5V, 6V, 8V, 9V 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, LM7806, LM7808, LM7809... accordingly. Also note that the capacitor must be replaced with the one that has voltage greater than the peak voltage.
Vpeak - 1.4 = (Vrms x √2) - 1.4
(12 x √2) - 1.4 = 15.6
hence filtered DC voltage applied to the input of LM7812 is 15.6V.
If you need output voltage of 5V, 6V, 8V, 9V 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, LM7806, LM7808, LM7809... accordingly. Also note that the capacitor must be replaced with the one that has voltage greater than the peak voltage.
No comments:
Post a Comment