I have a 24V AC power source (doorbell transformer).
Around that I'm hoping to build a circuit with two voltages:
1) 3.3V DC for an ESP8266 (for which I have a bridge rectifier and a D24V25F3 buck-down convertor)
and
2) 12V DC for a simple illuminated button (could also works with 5V or so, I don't need a bright light).
Idea:
I was looking for parts in an old DVD power supply board that I had around, and saw that it had multiple output voltages (25.5, 10.5, 6.3, 3.3). The transformer has 9 pins on the low voltage size and I realized that the voltage is probably split this way before regulating to those different desired voltages.
So it got me thinking, that instead of driving down ~34V DC one time to 12V and another to 3.3V, I could start by splitting the input into two 12V AC inputs, and that it would be simpler to get 12V DC from ~17V DC (maybe with a Zener diode?) instead of from ~34V.
Where I'm stuck:
So I looked for a center tapped 1:1 transformer and thought I could find a low voltage one that's the about the same size of an medium sized inductor, but my local place for electronics didn't really offer any, and looking online I mostly see 240/110V to 24V, etc. step down transformers. Rarely
I could find low voltage 1:1 transformers in some places, but they were described as pulse, RF or audio transformers and the prices did not make sense for me ($6 for the part, $30 for shipping) and I couldn't figure out if any of those would even fit my use case.
I'm curious why are those low-voltage 1:1 transformers aren't more common? What is the catch? What is the better alternative?
What would be a simple, yet efficient way to get the 12V and 3.3V DC supplies for this kind of small project?
p.s.
While writing the question and looking at Zener diodes, I got a sense that maybe it's not such a great idea and that instead it would be best to drop the 17V to 12V with a buck converter anyway. In which case I can just as well get a converter that's rated for 50V or so, and skip the magical tapped transformer that is much harder to find.
But thought I'll ask anyway, and learn as much as I can from the answers.
Around that I'm hoping to build a circuit with two voltages:
1) 3.3V DC for an ESP8266 (for which I have a bridge rectifier and a D24V25F3 buck-down convertor)
and
2) 12V DC for a simple illuminated button (could also works with 5V or so, I don't need a bright light).
Idea:
I was looking for parts in an old DVD power supply board that I had around, and saw that it had multiple output voltages (25.5, 10.5, 6.3, 3.3). The transformer has 9 pins on the low voltage size and I realized that the voltage is probably split this way before regulating to those different desired voltages.
So it got me thinking, that instead of driving down ~34V DC one time to 12V and another to 3.3V, I could start by splitting the input into two 12V AC inputs, and that it would be simpler to get 12V DC from ~17V DC (maybe with a Zener diode?) instead of from ~34V.
Where I'm stuck:
So I looked for a center tapped 1:1 transformer and thought I could find a low voltage one that's the about the same size of an medium sized inductor, but my local place for electronics didn't really offer any, and looking online I mostly see 240/110V to 24V, etc. step down transformers. Rarely
I could find low voltage 1:1 transformers in some places, but they were described as pulse, RF or audio transformers and the prices did not make sense for me ($6 for the part, $30 for shipping) and I couldn't figure out if any of those would even fit my use case.
I'm curious why are those low-voltage 1:1 transformers aren't more common? What is the catch? What is the better alternative?
What would be a simple, yet efficient way to get the 12V and 3.3V DC supplies for this kind of small project?
p.s.
While writing the question and looking at Zener diodes, I got a sense that maybe it's not such a great idea and that instead it would be best to drop the 17V to 12V with a buck converter anyway. In which case I can just as well get a converter that's rated for 50V or so, and skip the magical tapped transformer that is much harder to find.
But thought I'll ask anyway, and learn as much as I can from the answers.