Can DC voltage be doubled to drive 10 V relay ?

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

 

[Rich Webb]

On Tue, 07 Apr 2009 13:28:34 -0500, SidErraytor@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 are certainly DC-DC boost converters that take in 5 V and output
10 V, for example this is a drop-in module that does it:
<http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=296-20498-ND>

You can also roll yer own, with an oscillator, a couple of diodes, and
some caps. Although the output won't be quite 10 V, it may be in the
range that the relays will accept.

--
Rich Webb Norfolk, VA

 

[petrus bitbyter]

<SidErraytor@fishing.net> schreef in bericht
news:ur5nt4him4l7r31mtde4mjun9d2ji7v5u3@4ax.com...

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

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

 

[Nobody]

On Tue, 07 Apr 2009 13:28:34 -0500, SidErraytor 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 ?

Yes. The main options are:

http://en.wikipedia.org/wiki/Boost_converter
http://en.wikipedia.org/wiki/Voltage_multiplier

 

On Apr 7, 2:28 pm, SidErray...@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.

    Dave WB3DWE

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.

 

[Michael Black]

On Tue, 7 Apr 2009, SidErraytor@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.

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

 

[John Fields]

On Tue, 07 Apr 2009 13:28:34 -0500, SidErraytor@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.

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


JF

 

[Jasen Betts]

On 2009-04-07, SidErraytor@fishing.net <SidErraytor@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,

 

[amdx]

<SidErraytor@fishing.net> wrote in message
news:ur5nt4him4l7r31mtde4mjun9d2ji7v5u3@4ax.com...

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

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

 

[default]

On Tue, 07 Apr 2009 13:28:34 -0500, SidErraytor@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.

Dave WB3DWE

A simple circuit to double DC voltage:
http://www.elecfree.com/electronic/voltage-doubler-with-ic-555/

That will drive <100 milliamps as is. The 555 only provides a square
wave that is diode steered and added to the 5V already present.

IF you need more than 100 milliamps it may still work if the cap on
the output can fully charge before the relay pulls in, since the hold
current of a relay is much less than the pull in current (spec'd as
must actuate voltage and must release voltage).

Other, higher current, versions of the same basic circuit are on the
web . . . most use an Eccles/Jordan cross coupled two transistor
oscillator to do what the 555 does (but with more gusto).

But like others have said, if you have a source of unregulated power,
with a higher voltage, you can just use that.
--

 

[Tom Biasi]

"default" <default@defaulter.net> wrote in message
news:8qmmt4lvddnktsrh73bd5jsemao1kibf60@4ax.com...

On Tue, 07 Apr 2009 13:28:34 -0500, SidErraytor@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.

Dave WB3DWE

A simple circuit to double DC voltage:
http://www.elecfree.com/electronic/voltage-doubler-with-ic-555/

That will drive <100 milliamps as is. The 555 only provides a square
wave that is diode steered and added to the 5V already present.

IF you need more than 100 milliamps it may still work if the cap on
the output can fully charge before the relay pulls in, since the hold
current of a relay is much less than the pull in current (spec'd as
must actuate voltage and must release voltage).

Other, higher current, versions of the same basic circuit are on the
web . . . most use an Eccles/Jordan cross coupled two transistor
oscillator to do what the 555 does (but with more gusto).

But like others have said, if you have a source of unregulated power,
with a higher voltage, you can just use that.
--

Don't forget, the 555 can't go rail-to-rail and you will lose the diode
drops.
Tom

 

[default]

On Tue, 7 Apr 2009 10:19:58 -0400, "Tom Biasi"
<tombiasi@optonline.net> wrote:

Don't forget, the 555 can't go rail-to-rail and you will lose the diode
drops.
Tom

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.
--

 

[Jamie]

SidErraytor@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.

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.

http://webpages.charter.net/jamie_5"

 

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

 

[Jasen Betts]

On 2009-04-07, Jasen Betts <jasen@xnet.co.nz> wrote:

On 2009-04-07, SidErraytor@fishing.net <SidErraytor@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

 

[Ross Herbert]

On Tue, 07 Apr 2009 13:28:34 -0500, SidErraytor@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.
:
: Dave WB3DWE

You might like to try a MAX4624.
http://www.edn.com/contents/images/122001di.pdf

 

[Ross Herbert]

On 8 Apr 2009 11:20:52 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

:On 2009-04-07, Jasen Betts <jasen@xnet.co.nz> wrote:
:> On 2009-04-07, SidErraytor@fishing.net <SidErraytor@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.
http://www.freepatentsonline.com/4318154.pdf

 

[MooseFET]

On Apr 7, 11:28 am, SidErray...@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.

    Dave WB3DWE

How about buying a 10V supply and a LM7805?