Hi.
I intend to make a Linear Power Supply of 5v 3 amps, using a 9 volt transformer. Since I dont want the chassis to be bulkier due to the transformer inside, I wish to keep the Transformer away in a seperate enclosure and then extend the secondaries for about two feet to a smaller board which will house the rectifier and the filter caps and the regulator. I wanted to know if it's better to keep the transformer alone at that distance or wire the rectifier closer to the transformer and then wire the 2 feet cable out of it (DC) to the smaller board to connect the rest of the circuit.
Thank you
I intend to make a Linear Power Supply of 5v 3 amps, using a 9 volt transformer. Since I dont want the chassis to be bulkier due to the transformer inside, I wish to keep the Transformer away in a seperate enclosure and then extend the secondaries for about two feet to a smaller board which will house the rectifier and the filter caps and the regulator. I wanted to know if it's better to keep the transformer alone at that distance or wire the rectifier closer to the transformer and then wire the 2 feet cable out of it (DC) to the smaller board to connect the rest of the circuit.
Thank you
No big deal either way, distance is short and current not that high.
Not sure why you don´t just house PT and the rest of the supply in the same cabinet, simply for practical reasons.
Isn´t that a somewhat inefficient setup?
Generating 12V DC @ 3A and then linearly downregulating that to 5V sounds wasteful to me.
Not sure why you don´t just house PT and the rest of the supply in the same cabinet, simply for practical reasons.
Isn´t that a somewhat inefficient setup?
Generating 12V DC @ 3A and then linearly downregulating that to 5V sounds wasteful to me.
Thank you for your response. I' just want to do that for aesthetic reasons, to have a sleeker chassis next to the load than a bulkier one with a Transformer.
I did not understand the last part of your reply. I want to power a Raspberry pi which I use as a Music server. It needs 5 volts @ around 3 amps. I do not want to use a SMPS to do that. What else do you recommend ?
Thank you
Hi , at best use smps for powering digital parts ,not directly related to audio ( dac ) . For that power usage smps will be small size and will not need big heatsink for linear regulator and maybe for diode bridge too .
If you will power a dac , then linear regulator is needed after smps. Old style power supplies are sometimes required ,but not always. If you still want use that for raspbery ,then use different transformer ,with lower voltage ,use diode bridge from Schottky diodes ,and low drop regulator (not 7805).
If you will power a dac , then linear regulator is needed after smps. Old style power supplies are sometimes required ,but not always. If you still want use that for raspbery ,then use different transformer ,with lower voltage ,use diode bridge from Schottky diodes ,and low drop regulator (not 7805).
For 5V, 3 Ampere you need a good 6V transformer and a modern low noise LDO. I think R-Core transformers are produced in India.
Good experiences with LT1764. Forget the magic of switchers as that magic is not needed for such low power applications. The real magic is mainly how to solve the noise and RF the switchers introduce
Good experiences with LT1764. Forget the magic of switchers as that magic is not needed for such low power applications. The real magic is mainly how to solve the noise and RF the switchers introduce
+1.
I once had to mount a PT externally but the buzz-field was a big problem. Don't make big trucks drive the long way through town.
Yes, as others have mentioned, you've pretty much left the gate open with a design with just the TX in a box and everything else on the other side.
It can sometimes make sense to have TX plus bridge and prefiltering/preregulating in a separate box if high (or very fast) switching currents are involved, but for such low currents and voltages I would not personally bother. Either a switcher, or a small PCB mount TX plus bridge->filtering/decoupling, a sensible distance from the main PCB, or just isolated on the PCB layout by a few mm and with no ground plane under the TX (for myself). followed by local regulation and decoupling
In all cases the bridge and first stage filtering is next to the TX, to keep loop area small. this 'node' is always an area to pay close attention to WRT radiated noise, so stretching it over a few meters is not advised.
It can sometimes make sense to have TX plus bridge and prefiltering/preregulating in a separate box if high (or very fast) switching currents are involved, but for such low currents and voltages I would not personally bother. Either a switcher, or a small PCB mount TX plus bridge->filtering/decoupling, a sensible distance from the main PCB, or just isolated on the PCB layout by a few mm and with no ground plane under the TX (for myself). followed by local regulation and decoupling
In all cases the bridge and first stage filtering is next to the TX, to keep loop area small. this 'node' is always an area to pay close attention to WRT radiated noise, so stretching it over a few meters is not advised.
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