I'm a student doing research in a physics lab and we often have the need for a certain type of BNC cable splitter. This splitter has a BNC jack which accepts a single coaxial cable as input. It has two jacks for output. It routes the center pin of the input to the center pin of one of the outputs and it routes the shield of the input to the center pin of the other output.
To give an example, one thing we use this type of splitter for is to amplify a voltage (center pin) with respect to ground (outer pin) using a purely differential amplifier which takes two BNCs as input.
My questions are:
1. Is there a name for this type of splitter?
2. Is there anywhere that sells nice, high quality splitters of this type? We can homebuild them but it would be better if we can find a place to buy them from.
I've tried searching for this, but I haven't turned anything up. I appreciate any and all answers!
Edit: I should note that another thing we use this type of splitter for is connecting a two point resistance measurement from a multimeter to our breakout box. The multimeter has banana plugs and we want to connect the positive wire and the negative wire to different jacks on the breakout box (corresponding to different contacts on our sample inside a dilution refrigerator). It seems to me that a splitter like I described is necessary for this.
Best Answer
I don't think anyone really makes a connector like that. It really defeats the purpose of a differential amplification. I think a better solution would be to run the BNC cable straight into the + input of the amplifier and then terminate the - input or short it to GND. Or flip flop that if you want the output inverted. This will do exactly the same thing and you should get better noise performance as you will be bringing in less of the noise that will be coming back up the shield.
Edit: As for connecting to a multimeter, there are BNC to banana adapers available that will split out the center contact and shield on separate banana plugs. A couple of these in combination with a couple of banana cables would allow connections between the multimeter and any combination of signal and shield connections. However, this likely will not be very effective for performing sensitive measurements.