Solid state switch

[ryangoodner]

I have attached a schematic of the simple circuit I am working with. I have to replace Switch 1 with a combination of SCR's which will be powered by a 9v battery. Reason is I need the switch to be almost instantaneous which the mechanical switch currently does not achieve. Any help would be appreciated because I have no idea how to wire the SCR's to have them take the place of the switch!

 

[Hero999]

We've already told you.

https://www.electro-tech-online.com/threads/using-scrs-as-a-two-way-switch.104105/#post849746

The problem with using SCRs is that it's difficult to turn them off once they're on.

 

[ryangoodner]

I do not want to use the MOSFET as in the referenced post since this circuit will be connected to different sources and cannot have reliable resistance to influence the switching, which is why I want a way to use the SCR's

 

[Hero999]

Starting a new thread asking the same question isn't going to change the answer, it'll just cause people to loose their patience with you.

 

[ryangoodner]

Well I am sorry I frustrated you. I wanted this thread to be all about SCRs and not MOSFETS as the previous one was. I also included a schematic which I hope can help. Anyways... you stated that SCRs are difficult to switch off. This is acceptable because I only need the switch from 1-2 to 2-3 to happen once. Is their now a way anyone knows that can do this?

 

[Mike odom]

We've already told you.

https://www.electro-tech-online.com/threads/using-scrs-as-a-two-way-switch.104105/#post849746

The problem with using SCRs is that it's difficult to turn them off once they're on.

it's been a long long time since I've worked with SCRs, but I seem to remember once you turn them on you can't turn them off unless you interupt the current flow through them. With Triacs this isn't a problem because they switch ac and it goes to zero 120 times a second (100 for 50Hz).

 

[ryangoodner]

it's been a long long time since I've worked with SCRs, but I seem to remember once you turn them on you can't turn them off unless you interupt the current flow through them. With Triacs this isn't a problem because they switch ac and it goes to zero 120 times a second (100 for 50Hz).

"This is acceptable because I only need the switch from 1-2 to 2-3 to happen once."

 

[Hero999]

Well I am sorry I frustrated you. I wanted this thread to be all about SCRs and not MOSFETS as the previous one was.

Then why not state that in the original thread?

I also included a schematic which I hope can help.

You should've done that in the first place; always include a schematic if possible.

Anyways... you stated that SCRs are difficult to switch off. This is acceptable because I only need the switch from 1-2 to 2-3 to happen once. Is their now a way anyone knows that can do this?

Do you understand that: one you turn an SCR on, it will remain on until the power is interrupted?

Suppose you have 2 to 1 connected and you want to disconnect 2 to 1 and connect 2 to 3. The problem is, in order to disconnect 2 and 1, you need to disconnect the power to the whole circuit.

This is why we suggested MOSFETs because all you need to do is remove the gate signal and they turn off.

It doesn't matter how many threads you start or even if you ask the same question on another forum, the answer will be the same.

There's other important information you've missed:

If the switch going to be on the positive or negative side of the supply?

What signal are you using to switch it?

Then there' the information that you posted in the other thread which people responding to this one might have not read:

The voltage is 13V and current is 3.5A.