Can DC voltage be doubled to drive 10 V relay ?

If you are working from scratch I'd be inclined to say that it would be simpler to go ahead with a dual voltage power supply. You would not need a regulator onthe 10v if all you are doing is driving relays.

schreef in bericht news: snipped-for-privacy@4ax.com...

As so often, it depends. There are sure ways to double 5V, but what about the current? Those convertors have an efficiency of, let's say, 80%... If they are very good. So your 5V supply has to provide quite a lot of extra power. Then comes the calculation of costs. One or more voltage doublers that can provide enough current to handle the relays you need plus the extra powerfull 5V supply versus an extra 10V supply. Little more can be said without knowing the numbers you know.

petrus bitbyter

Yes. The main options are:

So what are you trying to do?

The simplest solution would be to get some 5v relays, and those are pretty common since 5v is a common voltage. But that only works if your relay need isn't esoteric, or requires contacts that can handle really large current.

Unless you are running this off batteries, you'll have a power supply that is likely to output more than 5v. Relays don't need regulated voltage, so you can run them off the DC coming out of the rectifier in the power supply. Use a transistor between the logic and the relay to deal with the larger voltage.

Michael

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How much current do your relays need, or, what\'s the coil resistance?

 
JF

there's a way to drive a 10V relay from a 5V supply it involves using a capacitor charged from the 5V to provide a pulse of 10V power and then running the relay off 5V which will be anough (in the absense of mechanical shock) to keep the relay turned on.

unfortunately I forget the details,

Where are you getting your 5 volts from, batteries or ac supply? If it is an ac supply, go back to before your 5 volt regulator and check the voltage, is it close to 10 volts? If it is, use it. If it's only 6.5 or 7 volts, you then you might need to go to the tranformer and build a voltage doubler to get voltage for your relay. Someone will need to draw this out because there might be some interaction between your existing

5 volt supply rectifier and the new voltage doubler circuit. Later, Mike

I haven't (really) forgotten it. Relays aren't precision devices so they have some latitude with pull in voltage. Most 5 volt relays are happy (MUST work) with 4.5V etc..

If the relay is exposed, it can be tweaked a bit by moving the mechanical stop and the voltage lowered, or raised.

I used the 555 circuit for another application - bought a circuit board intended for a LED IR floodlight, figuring all I had to do is use red leds and I'd have a motorcycle brake light - forget the Vdrop for a red led is higher than the IR . . .

I saw a similar circuit (Jasen Betts, refers to?) used a CMOS gate to make the oscillator and charge the output cap - once the relay pulls in the forward biased diodes in the doubler allow 5V to keep the relay pulled in.

Have some cheap 10 volt relays. My project will consist of 74HCT gates supplied by 5 volts. Is there any way of doubling 5 volts DC ? Otherwise I'll need a power supply that supplies multiple voltages.

Dave WB3DWE

If you can supply another voltage for the relays you can then use a open collector (common emitter) circuit driven from the outputs of the

5 volt logic to pull them down.. This will work out great since you would most likely need this transistor anyway to drive the relay coil.

Since Its assume you maybe using a 5 volt regulator, you should have some higher potential already there for the high side of the relay coils.

"

I think it was something like this: +5V ------ ---+-->|----+-[330]-- +5V _\\| / | + | ----- +--||----+ | | | | [330] +->|-+ | | | | | 0v-+- | [RLY] | | | +---[1K]--+----+ | / |/ in ----[1K]----| |\\| -\\ | -+- 0V

Thanks for all the thoughtful suggestions. I've learned a lot. Simplest solutions are to either get a 5 volt relay or another power supply. Dave WB3DWE

:Have some cheap 10 volt relays. My project will consist of 74HCT :gates supplied by 5 volts. :Is there any way of doubling 5 volts DC ? :Otherwise I'll need a power supply that supplies multiple voltages. : : Dave WB3DWE

You might like to try a MAX4624.

:On 2009-04-07, Jasen Betts wrote: :> On 2009-04-07, snipped-for-privacy@fishing.net wrote: :>> Have some cheap 10 volt relays. My project will consist of 74HCT :>> gates supplied by 5 volts. :>> Is there any way of doubling 5 volts DC ? :>> Otherwise I'll need a power supply that supplies multiple voltages. :>

:>

:> there's a way to drive a 10V relay from a 5V supply :> it involves using a capacitor charged from the 5V to provide a pulse :> of 10V power and then running the relay off 5V which will be anough :> (in the absense of mechanical shock) to keep the relay turned on. :>

:> unfortunately I forget the details, : :I think it was something like this: : : +5V : ------ ---+-->|----+-[330]-- +5V : _\\| / | + | : ----- +--||----+ : | | | : | [330] +->|-+ : | | | | : | 0v-+- | [RLY] : | | | : +---[1K]--+----+ : | : / : |/ : in ----[1K]----| : |\\| : -\\ : | : -+- 0V : :

What you mean is contained in this patent.

How about buying a 10V supply and a LM7805?