Hi
I'm a student right now that is lacking on funds! In my car I would like to put in some speakers, I've found some normal household speakers that would work great accept they run off 240v ac, I've opened them up and seen that they have a transformer dropping to 9v ac (The transformer reads 9V AC 1A). So i would like to cut out the middle man and just create 9v AC sine and wire it straight in. Obviously i would only need a very small circuit because of the small power need. Any help would be great!
You can cut out the middle man a bit more.
If you connect your 12VDC from your battery to where the 9VAC is connected your speakers will work. The reason is that the 9VAC goes into a bridge rectifier that allows the 12VDC to go through to power the electronics.
The disadvantage of this way is that you cannot connect to the input of your speakers a device that is powered by the car battery, you can connect only device that has its own battery.
Yes, very common to use 4 diode instead of a bridge. The cathode of 2 diode go to the + of the big capacitor and 2 anodes go to the - . When you power it up with 9VAC that capacitor has about 12VDC on it and when you connect 12VDC instead of 9VAC you get about 11V on the cap.
Yes, very common to use 4 diode instead of a bridge. The cathode of 2 diode go to the + of the big capacitor and 2 anodes go to the - . When you power it up with 9VAC that capacitor has about 12VDC on it and when you connect 12VDC instead of 9VAC you get about 11V on the cap.