hello everyone.
i´m doing a voltage source and i want to get approximately 30V500mA on Vout with the smallest ripple as possible. : i got a transformer 12 0 12 V and a 1000V 2A bridge rectifier and 4700uf 35V electrolytic capacitor. The thing is:
after rectifying it it should give me 24 * sqrt (2) = 33.9V which is more than I need. but the worst thing is that the transformer came to me badly regulated and it gives me 14.4V in each wire so I get 28.8V so after rectifying it I get approximately 38.4V which is a very large voltage. I need as close to 30V as possible. rectifying with the diode bridge that I have and after going through that capacitor it gives me as little ripple as I need but I have to lower that voltage somehow and I don't know how. I tried connecting a 2n3055 transistor and a 30V 200mA Schottky diode to it as shown in the picture, but doesn´t work. only lowers me to 38V.maybe putting a linear voltage regulator (it could be an LM317 (1.2V37V. 1.5A)) but I don't know if it would work. what do you think?
thnks!
i´m doing a voltage source and i want to get approximately 30V500mA on Vout with the smallest ripple as possible. : i got a transformer 12 0 12 V and a 1000V 2A bridge rectifier and 4700uf 35V electrolytic capacitor. The thing is:
after rectifying it it should give me 24 * sqrt (2) = 33.9V which is more than I need. but the worst thing is that the transformer came to me badly regulated and it gives me 14.4V in each wire so I get 28.8V so after rectifying it I get approximately 38.4V which is a very large voltage. I need as close to 30V as possible. rectifying with the diode bridge that I have and after going through that capacitor it gives me as little ripple as I need but I have to lower that voltage somehow and I don't know how. I tried connecting a 2n3055 transistor and a 30V 200mA Schottky diode to it as shown in the picture, but doesn´t work. only lowers me to 38V.maybe putting a linear voltage regulator (it could be an LM317 (1.2V37V. 1.5A)) but I don't know if it would work. what do you think?
thnks!
Attachments

23.5 KB Views: 21