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General Vintage Technology Discussions For general discussions about vintage radio and other vintage electronics etc. |
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10th Nov 2005, 1:22 pm | #1 |
Pentode
Join Date: Jan 2005
Location: Pant-y-Dwr, Powys, UK.
Posts: 134
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HT Power Supply from 12v Battery?
Hi,has anyone on the forum ever built an ht power supply using a 12v lead acid battery.I am currently trying to design a psu that will give me 144v at around 15ma.This is to supply my Lissen Conway battery wireless.I already have a 2v 12.5A/H cyclon cell for the lt supply.
I had originally thought about using 15 pp3 batteries but I think that these would only give about ten hours use.Rather expensive way of doing it! Any views or comments regarding this would be appreciated. Best Regards John. |
10th Nov 2005, 1:33 pm | #2 |
Octode
Join Date: Nov 2003
Location: Bath, Somerset, UK.
Posts: 1,804
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Re: HT Power Supply from 12v Battery?
John, there was an article in one of the BVWS bulletins about six years ago where a 12V lead acid battery was used to power up an eliminator. The designer made it to match a mid '20s set, using it as a plinth. I seem to remember that it used a switch-mode circuit.
Neil |
10th Nov 2005, 1:46 pm | #3 |
Rest in Peace
Join Date: Feb 2004
Location: Hexham, Northumberland, UK.
Posts: 2,234
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Re: HT Power Supply from 12v Battery?
I have tried various designs for invertors and had difficulties with no-load regulation. High frequency designs are probably more efficient but can produce "hash" that interferes with medium/long wave reception. I have had good results by driving a mains transformers in reverse at about 100Hz. This does not seem to produce interference. This may not be the ideal way to do it though and I'm sure the other forum members will have some good ideas on this.
Biggles |
10th Nov 2005, 1:48 pm | #4 |
Dekatron
Join Date: Jan 2004
Location: Newcastle upon Tyne, Tyne & Wear, UK.
Posts: 8,173
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Re: HT Power Supply from 12v Battery?
Hi Gents, you will need some sort of inverter to do this, I believe there are some commercial units and designs out there, but the main problem is the interferencefrom the inverter itself causing unwanted noise on the receiver it is operating. This csn vary greatly between sets. try and get one that operates at a low frequency, or you could look for an old vibrator as used on car radios and make an inverter from that. They typically operated at 400Hz, but could still produce some hash on the sets they were powering.
HTH Ed |
10th Nov 2005, 1:50 pm | #5 |
Pentode
Join Date: Jan 2005
Location: Pant-y-Dwr, Powys, UK.
Posts: 134
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Re: HT Power Supply from 12v Battery?
Hi Neil,I am going to be using a simple oscillator circuit and a transformer to step the voltage up.I am going to have to order some fast recovery diodes for the bridge rec circuit as I dont think a standard bridge rec is up to the high frequency.I'm also planning on limiting the voltage using a 150v zener at the output.
Regards John |
10th Nov 2005, 7:04 pm | #6 |
Retired Dormant Member
Join Date: Sep 2003
Location: Wrexham, North Wales, UK.
Posts: 799
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Re: HT Power Supply from 12v Battery?
Hi there is a design for one of these PSU's in the December issue of Everyday & Practical Electronics I saw it in WH Smith this afternoon HTH
Mike |
13th Nov 2005, 1:55 pm | #7 |
Pentode
Join Date: Jan 2005
Location: Pant-y-Dwr, Powys, UK.
Posts: 134
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Re: HT Power Supply from 12v Battery?
Hi Mike,I have just bought the Dec issue of epe and their design for an ht psu looks very interesting.It's good in that the oscillator runs at 53hz so no nasty rf noise will be generated.
Regards John. |