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1.5VDC Relay..

R

Ross Irvine

Jan 1, 1970
0
Hi All,

I need some 1.5VDC Relays (Trigger/Contact voltage).
I've check DSE, radio parts, jaycar and I'm struggling to find relays
that will trigger at this low voltage. I've found 5 and even 3.5VDC but
I need 1.5VDC.

Any ideas?

Thanks,

Ross.
 
M

Mike Harding

Jan 1, 1970
0
I need some 1.5VDC Relays (Trigger/Contact voltage).
I've check DSE, radio parts, jaycar and I'm struggling to find relays
that will trigger at this low voltage. I've found 5 and even 3.5VDC but
I need 1.5VDC.

Don't think I've ever seen of 1V5 mechanical relays.

Tell us the application - in detail - and we may be
able to suggest other options.

Mike Harding
 
P

Phil Allison

Jan 1, 1970
0
"Ross Irvine"
I need some 1.5VDC Relays (Trigger/Contact voltage).


** Huh ???????

Please explain.

Most relays have coil voltage ratings and DC and AC breaking capacity
ratings.

Then there are all the special types.



............ Phil
 
R

Ross Irvine

Jan 1, 1970
0
Hi Mike,

I have a 1.5VDC wireless doorbell (the 'bell' runs on 1.5VDC) that I
want to hook into my Alarm/Home Automation system. The easy solution is
to attach a relay to the wireless 'bell' which loops a NC or NO contact
back to the alarm panel. There are plenty of contacts on the wireless
bell's PCB which energises 1.5VDC (It runs on 2 * 1.5 D size batteries)
when the doorbell "rings" which I can use to close a relay. The relay
closes, the alarm panel 'sees' the zone change then I can act on it.
The problem is finding some type of relay system that'll work with such
low voltages.
As the doorbell itself (not the remote that you push) just runs on it's
own batter power it would be good to be able to utilise its own power
rather than running 12-24VDC to it just to power a relay or some other
device

Thanks,

Ross.
 
C

Clifford Heath

Jan 1, 1970
0
Ross said:
I need some 1.5VDC Relays

I think I've seen reed relays that work at this voltage,
if that would work for you (normally-open...)
 
M

Mike Harding

Jan 1, 1970
0
I think I've seen reed relays that work at this voltage,
if that would work for you (normally-open...)

Can't see any reed relays below 3V5 in Farnell/RS.

Mike Harding
 
J

John Crighton

Jan 1, 1970
0
Don't think I've ever seen of 1V5 mechanical relays.

Tell us the application - in detail - and we may be
able to suggest other options.

Mike Harding

Hello Mike,
Funny thing, I was just reading a railways signalling manual
the other day called "Track Circuits" and there was a
description of low voltage relays and single wet cells for
powering the circuit and the relay coils. From memory they
pulled in at just over a volt and dropped out just under a volt.
They were huge, about half a house brick in volume.
Regard,
John Crighton
Hornsby
 
M

Mike Harding

Jan 1, 1970
0
Funny thing, I was just reading a railways signalling manual
the other day called "Track Circuits" and there was a
description of low voltage relays and single wet cells for
powering the circuit and the relay coils. From memory they
pulled in at just over a volt and dropped out just under a volt.
They were huge, about half a house brick in volume.

They would be too :)

And not only large in size but _very_ large in price too
I suspect. Usually that sort of stuff has to be "fail safe".

Mike Harding
 
J

Josh

Jan 1, 1970
0
Ross said:
Hi Mike,

I have a 1.5VDC wireless doorbell (the 'bell' runs on 1.5VDC) that I
want to hook into my Alarm/Home Automation system. The easy solution is
to attach a relay to the wireless 'bell' which loops a NC or NO contact
back to the alarm panel. There are plenty of contacts on the wireless
bell's PCB which energises 1.5VDC (It runs on 2 * 1.5 D size batteries)
when the doorbell "rings" which I can use to close a relay. The relay
closes, the alarm panel 'sees' the zone change then I can act on it.
The problem is finding some type of relay system that'll work with such
low voltages.

what about using an optocoupler eg. 4n25?

josh
 
M

Mike Harding

Jan 1, 1970
0
what about using an optocoupler eg. 4n25?

Hmmm... Ross's post didn't show on my news server, too many
of those on Ihug for my liking, anyway...

At 1V5 an opto coupler may not work - but as you only want
one you may be able to select a particular one which will.

Otherwise just use a basic NPN transistor BC337 or similar
with a 1K resistor in the base. If you don't understand this
let me know and I'll do an ASCII drawing.

Oh well, I'll do it anyway: (fixed font)

C/--------> Alarm panel
/
B|/
Doorbell <------- 1K resistor ------- |
|\
\
E\
|
|
0V on both doorbell and alarm


You may need a resistor (1K?) from the BC337 collector to 12V
(or whatever on the alarm panel).


Mike Harding
 
T

Trevor Wilson

Jan 1, 1970
0
Ross Irvine said:
Hi All,

I need some 1.5VDC Relays (Trigger/Contact voltage).
I've check DSE, radio parts, jaycar and I'm struggling to find relays
that will trigger at this low voltage. I've found 5 and even 3.5VDC but
I need 1.5VDC.

Any ideas?

**There are quite a number of possible solutions. None of which involve a
1.5 Volt relay. What is the precise application?
 
R

Ross Irvine

Jan 1, 1970
0
Hi Trevor,

I have a 1.5VDC wireless doorbell (the 'bell' runs on 1.5VDC) that I
want to hook into my Alarm/Home Automation system. The easy solution is
to attach a relay to the wireless 'bell' which loops a NC or NO contact
back to the alarm panel. There are plenty of contacts on the wireless
bell's PCB which energises 1.5VDC (It runs on 2 * 1.5 D size batteries)
when the doorbell "rings" which I can use to close a relay. The relay
closes, the alarm panel 'sees' the zone change then I can act on it.
The problem is finding some type of relay system that'll work with such
low voltages.
As the doorbell itself (not the remote that you push) just runs on it's
own batter power it would be good to be able to utilise its own power
rather than running 12-24VDC to it just to power a relay or some other
device

Thanks,

Ross.
 
R

Ross Irvine

Jan 1, 1970
0
Never used Opto couplers before.

Reading some specs it seems in it's simplest format it can be used as a
relay.

Energise PINS 1 and 2, shorts pins 4 and 5 together.

Is this right?

Thanks,

Ross.
 
J

JDH

Jan 1, 1970
0
Ross,

What about a solid state relay, they may operate from a lower voltage, also
maybe a DC/DC converter prior to a relay that normally needs atleast 3 to 5V
is also a solution.

Regards,

John.
 
T

Trevor Wilson

Jan 1, 1970
0
Ross Irvine said:
Hi Trevor,

I have a 1.5VDC wireless doorbell (the 'bell' runs on 1.5VDC) that I
want to hook into my Alarm/Home Automation system. The easy solution is
to attach a relay to the wireless 'bell' which loops a NC or NO contact
back to the alarm panel. There are plenty of contacts on the wireless
bell's PCB which energises 1.5VDC (It runs on 2 * 1.5 D size batteries)
when the doorbell "rings" which I can use to close a relay. The relay
closes, the alarm panel 'sees' the zone change then I can act on it.
The problem is finding some type of relay system that'll work with such
low voltages.
As the doorbell itself (not the remote that you push) just runs on it's
own batter power it would be good to be able to utilise its own power
rather than running 12-24VDC to it just to power a relay or some other
device

**Then I would consider using one of these:

http://tinyurl.com/4aba2

Although it states that it is suitable for 3 Volt operation, I am pretty
certain that it works down to 1.5 Volts. DON'T spend any money, 'till you're
certain though. I built one a few years ago, I think it worked OK on 1.5
Volts. I'll try to find it and let you know.

At present I am mucking about with some solar powered garden lights, which
were on special at Flower Power http://www.flowerpower.com.au/ last
weekend. A pair of lights was marked down to 13 Bucks. They had a couple of
hundred in stock on Sunday. Anyhoo, they operate a white LED from a 1.5 Volt
battery. There's a little PCB inside, which I assume converts the 1.5 Volts
to something a little higher. I'll let you know how I go. I wanted to 'hot'
mine up, using some Lumileds. One of these might be useful for your
purposes.

BTW: Most of the light seems to be lost by the (crappy) diffuser in these
things.
 
R

Ross Herbert

Jan 1, 1970
0
Can't see any reed relays below 3V5 in Farnell/RS.

Mike Harding


Normally, reed relays for general purpose apps don't come below 3V.
However, special purpose polarised reed relays are manufactured for
high sensitivity functions in the telephony area. I have some single
c/o units on hand manufactured by IEI Japan (STC subsidiary but no
longer in existence) which measure 52L x 15W x 14H which operate down
to 1.0V
 
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