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Amp draw of coil based relays

I

Ignoramus21666

Jan 1, 1970
0
Does anyone have any idea as to how many milliamps do small coil based
relays (12v coil) draw, typically?

i
 
T

Tim Shoppa

Jan 1, 1970
0
Does anyone have any idea as to how many milliamps
do small coil based relays (12v coil) draw, typically?

Automotive relays are typically 150-200mA ("72 ohm coil").

Smallish reed relays with 12V coils are in the 12mA range. ("1K ohm
coil").

As I hint above, relay specs are typically given in coil resistance.

Tim.
 
S

Spehro Pefhany

Jan 1, 1970
0
Does anyone have any idea as to how many milliamps do small coil based
relays (12v coil) draw, typically?

i

Depends on what you mean by small, but small power relays (eg. a few
A) typically consume in the hundreds of mW (eg. 360mW). At 12V, that's
30mA. You can probaby find some in the 100mA range. Generally, coil
power goes up with switching current, lifetime and voltage isolation,
so relays made to more stringent European safety standards tend to use
a bit more power.


Best regards,
Spehro Pefhany
 
I

Ignoramus21666

Jan 1, 1970
0
Thanks, Spehro, Tim, and Dan.

I am trying to buy some cheap relays to let my kid play with his toy
LifeLike railroad.

He is very much into traffic lights and this railroad.

For example, if a train approaches a RR traffic light, and it is red
or yellow, stop the train. If a train approaches a crossing, light red
light on the crossing. Etc. It should be very easy with a 12v power
supply and some relays and alligator clips, and maybe light switches
or some such.

We already have a power supply, traffic light etc.

So, I am looking to buy some cheap 12v coil relays. Hence my question.

i

If you know the make an model you can look it up

Or

You can measure the coil resistance with an ohm meter and calculate it

Dan


--
 
J

John Fields

Jan 1, 1970
0
Thanks, Spehro, Tim, and Dan.

I am trying to buy some cheap relays to let my kid play with his toy
LifeLike railroad.

He is very much into traffic lights and this railroad.

For example, if a train approaches a RR traffic light, and it is red
or yellow, stop the train. If a train approaches a crossing, light red
light on the crossing. Etc. It should be very easy with a 12v power
supply and some relays and alligator clips, and maybe light switches
or some such.

We already have a power supply, traffic light etc.

So, I am looking to buy some cheap 12v coil relays. Hence my question.

---
Potter and Brumfield T7NS5D1-12

http://relays.tycoelectronics.com/datasheets/T7N_DS.pdf

Digi-Key and Mouser both stock them at $1.32
 
I

Ignoramus21666

Jan 1, 1970
0
Potter and Brumfield T7NS5D1-12

http://relays.tycoelectronics.com/datasheets/T7N_DS.pdf

Digi-Key and Mouser both stock them at $1.32

Thanks. I bought some 50 Sigma 12v 4 pole SPDT relays at 60 cents apiece
on ebay... I hope that they should work fine. The power supply has
quite a bit of extra power available after powering the toy train, so
amp draw of coils should not be a huge issue.

i
 
R

Robert Latest

Jan 1, 1970
0
On Tue, 06 Dec 2005 17:59:03 GMT,
Ignoramus21666 said:
Does anyone have any idea as to how many milliamps do small coil based
relays (12v coil) draw, typically?

Datasheets and ammeters usually have pretty good ideas about how much
current things draw.

robert
 
Robert said:
On Tue, 06 Dec 2005 17:59:03 GMT,


Datasheets and ammeters usually have pretty good ideas about how much
current things draw.

robert

and little kids have fairly good ideas of how to wreck ammeters :) But
I quite agree, it would be the thing to get for them.

NT
 
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