Low current triggered relay, need help on specs/which will work

[teknochild]

I Need a normally closed relay (can be normally open if it has to be I guess) that can be switched by less then 1mA @ 11 volts (1.25mA 11.35v to be precise) and handle a load of 8mA @11v (7.5mA 11.35v to be precise).

I'm pretty sure what I need is a solid state relay, but I can't seem to find anything. A Google search yields a few things but nothing concrete. Looking here https://www.vishay.com/solid-state-relays/ I found a few things that might work, but I don't understand half the specs on the data sheets. I've used regular relays for various things in the past but these go a bit over my head.



Basically I'm trying to fool a 3 position magnetic induction sensor into thinking that position 3 is switched at the same time as position 2. Position 2 sends a constant 1.25mA @11v until it's switched (and turns off) and I want to use this to switch a relay which will provide the position 3 wire with the 8mA @11v as soon as position 2 is switched.



My other concern is do SSRs have to have their current controlled (As in probably can't just give it any power source and ground it without burning out?)

 

[Mikebits]

I Need a normally closed relay (can be normally open if it has to be I guess) that can be switched by less then 1mA

You will be hard pressed to find a relay that activates by 1 ma. Consider a FET to turn the relay on.

 

[Boncuk]

Use an analog switch (CD4066). Activation is at far less than 1mA and paralleling all four in a package you are on the safe side. (for output current)

Analog switches are normally open. Use an inverter (transistor, BC547) for NC- normally closed operation.

Supply voltage of 12V will be sufficient.

SSRs and reed relays require 10mA for reliable operation. However you can't use an SSR anyway for this low current to switch.

Boncuk

 

[teknochild]

There's a whole host of SSRs at that link that can be activated by 1mA or less... I just don't understand the rest of the specifications which is what I am asking about.

For instance: https://www.electro-tech-online.com/custompdfs/2008/08/vo1400ae.pdf
Or: **broken link removed**



Boncuk I'll see if I can read up on what you suggested, but that's foreign to me.

 

[mneary]

Do you need isolation between input and output?

 

[teknochild]

Do you need isolation between input and output?

I guess not, I explained the situation, you guys would know better then me honestly.

 

[rjvh]

never seen relais that switched on 1ma

try to steer it with a fet the BS170 or its sister BS250 would be able to switch that

Robert-Jan

 

[teknochild]

never seen relais that switched on 1ma

Again:

There's a whole host of SSRs at that link that can be activated by 1mA or less... I just don't understand the rest of the specifications which is what I am asking about.

For instance: https://www.electro-tech-online.com/custompdfs/2008/08/vo1400ae-1.pdf
Or: **broken link removed**

Unless I am mistaken.

 

[teknochild]

Seriously though I think you guys are assuming me to be more knowledgeable then I am. I really don't know half of what your saying or 80% of whats on the data sheets of the things you guys are suggesting (or how to use them).

 

[Boncuk]

Hi technochild,

most of the members here assume that such posts are done to do somebodies homework and therefor you have a small problem.

I have never seen an SSR switching at 1mA.

I had a serious computer breakdown (installing antivirus software which behaves worse than the worst virus I know of)

Here is a screenshot I just managed to to. The circuit is drawn the way you want to switch: normally closed. Pressing S1 will open the switches.

Boncuk

 

[Mikebits]

There's a whole host of SSRs at that link that can be activated by 1mA or less... I just don't understand the rest of the specifications which is what I am asking about.

For instance: https://www.electro-tech-online.com/custompdfs/2008/08/vo1400ae-2.pdf
Or: **broken link removed**

Based on your supplied data sheet. If you look at attached image. 1ma is a butt hair away from not working. Your first goal should be to find a way to increase your current drive with something like a buffer or such.

 

[rjvh]

Hi you can use a inverter port CD 40106 they are verry sensitive and the output is strong enough to steer a transistor

see atached schematic

Robert-Jan

 

[teknochild]

Hi technochild,

most of the members here assume that such posts are done to do somebodies homework and therefor you have a small problem.

Don't think I would have as much trouble if it was. I'm not an electrical engineer or going to school to be one. That's my small problem .

I hate to ask but can someone just tell me what electronics piece I need and how to wire it based on what I said in the first post. The diagrams and stuff don't really help me because I don't know what they say. My electronics knowledge is very basic. Don't get me wrong though I've looked up all the data sheets of the pieces you guys suggested, and tried to research what I need to do but cant really understand it.