I have two speaker protection boards by JLester which needs 15VAC 1A each.
What do I need? I believe it's enough with a transformer that has 15VAC secondary, and no other components what so ever. But I ask because I'm not sure. No diodes , protection, anything?
What do I need? I believe it's enough with a transformer that has 15VAC secondary, and no other components what so ever. But I ask because I'm not sure. No diodes , protection, anything?
You would probably need a fuse to ensure your house won't burn down if the transformer or the speaker protection board should develop a short circuit.
Haha, I figured, but thanks for reminding me. I was just curious if the transformer itself actually is enough. My ignorance feels like something else is missing.
To keep it simple: Yes, if you have 230VAC and the load wants 15VAC, you only need a 230VAC:15VAC transformer of appropriate size.
To also keep you safe, you want a fuse so a fault does not heat-up your line cord, set the carpet on fire, burn-up your house. And a box so your child/cat does not touch live wires. You may also want a switch. In some lands a commercial product must use a 2-pole switch. If the box is metal (plastic boxes should be Approved for hiding live wires, so not a cookie-tray) and you have a 3rd pin (PE, green wire) on your wall outlet, there should be a substantial bond from wall 3rd pin to bare metal on the box, so a loose wire will blow the fuse in the basement before anybody gets shocked.
To also keep you safe, you want a fuse so a fault does not heat-up your line cord, set the carpet on fire, burn-up your house. And a box so your child/cat does not touch live wires. You may also want a switch. In some lands a commercial product must use a 2-pole switch. If the box is metal (plastic boxes should be Approved for hiding live wires, so not a cookie-tray) and you have a 3rd pin (PE, green wire) on your wall outlet, there should be a substantial bond from wall 3rd pin to bare metal on the box, so a loose wire will blow the fuse in the basement before anybody gets shocked.
Are there regulators on board ? Perhaps You will need not 15V AC, but slightly a couple of Volts more in order for them to work. For example a 7815 needs more 3V on the input.
He says the circuit needs 15V AC. If that is what the designer has asked for then he will already have taken account of what the DC arrangements are.
A transformer rated for 15VA (15V, 1A) will not burn any house still under shortcircuit conditions. The finest of the primary winding will act as a self fuse. In any case, external fusing and or a thermal cutout is recommended.
