I bought a BK Precision 9123A power supply on ebay for about $200, but it didn't come with cables.

If you look on the product page here or the image below you can see the type of connectors is has on the front of it.

I've tried searching on ebay using various key words, but can't find the right kind of cables. So, I've concluded that there must be a special name for them, which is... ?? BK precision 9123A power supply front side.

  • 1
    \$\begingroup\$ "Sheathed banana plug terminals" just like it says on the page you linked. The "sheathed" part is irrelevant. You will be okay with any kind of banana plugs. \$\endgroup\$
    – The Photon
    Commented Mar 19, 2012 at 2:27
  • \$\begingroup\$ Also called "4 mm" plugs. But I had to look in Wikipedia to remember the dimension. \$\endgroup\$
    – The Photon
    Commented Mar 19, 2012 at 2:29
  • \$\begingroup\$ These are the standard for lab power supplies, it would be surprising if they used anything else. \$\endgroup\$
    – starblue
    Commented Mar 19, 2012 at 18:54

3 Answers 3


Most power supplies come with the standard banana connectors and screw-on terminals. The BK 9213A has a datasheet link that specifically states banana jacks,

If you don't have the banana connector on hand, you can also screw a wire into a hole in the banana jacks.

However, buying banana connectors is definitely the right way to go for long term use.

  • 2
    \$\begingroup\$ In this case he can't, because the connector is different (no screw). \$\endgroup\$
    – clabacchio
    Commented Mar 20, 2012 at 13:58

Those look like banana connectors to me.


Those are 4mm shrouded banana connectors. They are seen on electronics lab equipment, such as power supplies, multimeters, test probes with removable leads and various other (sometimes custom) gear. It's basically the go-to connector when you need a touch-safe single pole connector for lab use.

Plugs, both straight and stackable and readymade leads are available from most good electronics suppliers, search for "4mm shrouded" and you should fine them.

You can plug an unshrouded banana plug into a shrouded socket and this is a reasonable thing to do if you are working at safe voltages.

Contary to lyncas answer, you can't directly use bare wires with your power supply. Many power supplies come with binding posts that can take either bare wires or a 4mm connector, but yours is not one of them.

In my experiance lab power supplies normally have either 4mm shrouded sockets (which can take either shrouded or unshrouded 4mm plugs, but not bare wires) or "binding posts" that can take either bare wires or unshrouded 4mm plugs but not shrouded 4mm plugs. I have occasionally come across power supplies with binding posts that could take shrouded plugs but they don't seem to be common.


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