Electronics 2000

Hi

I Need to power a RF amplifier which needs 28v - 2.8a. But then iv also got to power 2 other devices which need 12v each. and about 1a.

iv worked everything out apart from this, how could i do this ? Iv drawn a diagram of what im building.



thanks, Bryan

How accurate does it need to be?
I have a 28V petrol driven battery charger which is designed to charge 24v batts.
Is the current through the 12v systems constant....

Back tonight.

I basically need to power everything with the same power supply, so i went for the most powerful device first, 28v then try to step down from that to 12v and power the others.
and im not sure but i think everything should be constant, i think you mean DC.

No, I mean I dont know if the current is allways 1A and 0.3A ... may be some times it is 0.5A`and 0.1A etc... if the (12V)currents are always the same, a resistor in parallel with the 0.3A load of the correct size would give 1A and 1A, in which case you could connect both 12V circuits in series and connect them to the 28V supply...
I dont know much about ths circuit it looks sensitive ... I would not recomend doing that without a good deal of thought.

I think you could get a voltage converter (ebay) which converts 24V to 12V...
A car is refered to as 12V but in fact it charges at 14.41V ... when you say 28V hmmm I dont want to waste you equipment ... A voltage converter will sort it... I prob think.

Iv decided to use one of those 12v power supply's in the plastic cases to do the other 2 devices, and use the main power supply to power the amplifier, ill wire both power supply's up to the AC and have it running as one. there is a way to do it with 1 psu but i dont know how.

I am not sure but I think wireing all negatives to chassis... may be a good idea, I think hmmm... What is this thing any way it is unclear...
How about a photo...

Back in a bit.

its an fm transmitter, now running with 2 power supplys