How do you make a switch?

[wallyuwl]

For my dissertation I need to use two different muscle stimulators. They would each output into male BNC connectors. I need these connectors to go into a box, and from that box flip a switch that will determine which electrical signal (i.e.: from what stimulator) it lets through. I need these to go to one output (type of output doesn't matter, I have adapters, etc.).

In my head it would function sort of like a speaker selector box.

Any suggestions on how to do this? Or where I could go to find out?

 

[HerrStig]

Originally Posted By: wallyuwl
For my dissertation I need to use two different muscle stimulators. They would each output into male BNC connectors. I need these connectors to go into a box, and from that box flip a switch that will determine which electrical signal (i.e.: from what stimulator) it lets through. I need these to go to one output (type of output doesn't matter, I have adapters, etc.).

In my head it would function sort of like a speaker selector box.

Any suggestions on how to do this? Or where I could go to find out?


If you are using coax cable, an antenna swtich with the proper connectors would be fine. Google RF antenna switch. Isolation between ports on a good one is very high. try "Ham Radio Outlet" or "AES" on line by googleing.

 

[440Magnum]

What's the maximum frequency content of the signal your switching? If its in the kilohertz range, open wiring inside a metal box connected to a dual-pole dual-throw switch is sufficient. For 100s of kHz up to the MHz range, an RF coax switch as mentioned by another poster would be recommended. Ham radio store will get R done for you. You'll probably need adaptors from a PL-259 ("UHF") connector to BNC, but you can get those from Pasternack or elsewhere.

 

[wallyuwl]

Thanks guys.

This is essentially what I'm looking for: http://www.ambery.com/2in1outbncco.html

It is for video, but a signal should be a signal, right? Or no?

The frequency of the inputs would be sometimes 1 Hz every few seconds, and at other times 200 Hz but only for two pulses at that frequency. The voltage and amperage will vary (400 volts @ 150 mA would be about the max input into the switch, and subsequently output out of the switch).

 

[MolaKule]

What are the pulse width, and rise and fall times of the pulses?

 

[wallyuwl]

Pulse width will be mostly 1 ms, but some will be shorter. Rise and fall will be immediate.

 

[440Magnum]

Originally Posted By: wallyuwl
Pulse width will be mostly 1 ms, but some will be shorter. Rise and fall will be immediate.



So an audio frequency switch should be fine (btw- rise and fall is never "immediate," but on the time scale of a pulse width being 1 ms it can seem immediate.)