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wanted : 12vdc to 24vac 5 watt schematic

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hi, has anybody got link / schematic for a 12vdc to 24vac ( 5 watt) converter , its to power a digital color board camera,.

i`ve been doing a fair bit of looking around online , but come up with nothing. some have posted same type of question , even they have come up with no schematics etc no usefull information .....

converter must operate from 12vdc ( battery ) , mains power is not a option .
not interested in buying one already made.

any one help ?
thanks, mark k
 
Sir mark krawczuk . . . . . . .



Is that "24vac" spec chiseled in stone,as you are probably then going to have to rectify it to DC anyhow, aren't you ?
If so, would a PRECISE frequency output be a requirement ?

73's de Edd
 
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Sir mark krawczuk . . . . . . .



Is that "24vac" spec chiseled in stone,as you are probably then going to have to rectify it to DC anyhow, aren't you ?
If so, would a PRECISE frequency output be a requirement ?

73's de Edd
hi, chisled in stone ? well , its a digital color board camera and it says it needs 24vac , ( 50 hz) to work... so i DONT need to rectify it to dc. the ac goes straight to the pcb.

mark k
 
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hi, as stated in my first post it HAS to be battery powered . mains is NOT a option,
i will be goin out bush and need it portable.
i cant understand no one seems to understand my post where i say mains power is not a option.....

mk
 

davenn

Moderator
if you cannot find one that goes to 24 VAC
you may have to use one that goes to 240 VAC and then use a transformer to take the 240 VAC back down to 24 VAC
 
You do not say what frequency or votage accuracy you want or the waveform.
A simple supply can be made with a centre tapped transformer driven by two fets and controlled by a 4047. There will be approximately 24V square wave across the entire winding.
There may be problems with isolation.
 

hevans1944

Hop - AC8NS
Many el-cheapo inverter circuits do not provide clean sine waves at a stable frequency. If that doesn't bother you, a simple two-transistor-plus-transformer inverter as suggested in post #8 by @duke37 will do. There are many schematics on the Internet. Here is one place to start looking. You will have to adapt most of the designs to use a transformer with a low-voltage secondary (output) winding since most of the authors seem to think everyone wants either 110 VAC or 220 VAC power.
 
Sir mark krawczuk . . . . . . .

so i DONT need to rectify it to dc. the ac goes straight to the pcb.


OK then, I will need to further clarify my initial thought train for you .

The "24VAC" aspect immediately triggers the fact that a GOOD amount of commercial security cameras installations still depend upon 24VAC power routed to them.

Your units model number and brand would have initially be of a great help, AND STILL IS, because of need to research its schematic for some answers.
Considering, that units schematic is floating around to be able to consult . . . beyond that, it would have to be reverse circuitry engineered.

I highly suspicion that all one needs is a connection of a 12VDC or 24 VDC battery into that power connector.

Then the initial full wave bridge rectifier inside of that unit , which would normally be converting your AC voltage to DC voltage , would stop having that designation and is then merely being a DC directional coupler.
The DC then ends up across the systems main input electrolytic filter capacitor . . .which is now only serving as a storage reservoir enhancing function , since DC is INITIALLY already being present .
The rest of the power supply circuitry then takes its needs for creating other power supply branches and DC levels.

The "50 cycle" aspect is of no consequence, since it was just a "baggage" product of having been associated with having taken power from the mains.

Since the 70's and 80's any internal circuitry with critical frequency or timing aspects would not be relying upon 50~ referencing .
Instead, crystal or ceramic resonators associated with a microprocessor(s) or ancillary circuitry would be attaining any of those critical needs.


73's de Edd
 
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