Power Supply test leads - Page 1
Forum section: electronics / beginners

author: bizarrefish
author_rank: Newbie
timestamp: January 16, 2024, 11:16:16 pm
content: Hi all,Looking to get into Electronic Engineering as a moderate mid life crisis, which will no doubt suck me in as I have a disposition to it. I have a long history of hobbyist in everything RC and computers (my current career) and long held a desire to understand EE to a greater depth.My first lab bench equipment will be a power supply that will offer me flexibility to be useful to existing hobbies and to begin some projects / troubleshoot & repair toys / devices. My ask here is the following;1. What test leads would you recommend I buy or build first?2. If buy, any recommendations on kits or suppliers?3. If build, any recommendations on makes of connectors? Digikey and Mouser are a minefield and if I am building would prefer to do it once with quality connectors.My current thoughts on leads are the following;1. 4mm banana to 4mm banana2. 4mm banana to 2.1MM DC jack barrel3. 4mm banana to 2.5MM DC jack barrel4. 4mm banana to EC8 connector (for RC iCharger battery charging)5. 4mm banana to USB A6. 4mm banana to USB CFeel free to shoot me down, push/pull me in a different direction.I have searched the forums but dont see anything related to leads for DC jack barrel charging only and cannot find the right search in google to pull up pre-made leads so suspect this is a build item and Im seeking recommendations on connectors.Thanks in advanceRichard

author: Benta
author_rank: Super Contributor
timestamp: January 16, 2024, 11:45:34 pm
content: It's unclear to me if you already have a power supply or not.You ask a lot of questions about the cables.If you're looking for the PSU itself, it should have:Dual independent outputs, each 15...30 V, 3 A.Independent displays for voltage and current on both outputs.Adjustable current limit for each output.A bonus would be a separate 3.3/5.0 V output.The leads are the second consideration.

author: WimWalther
author_rank: Regular Contributor
timestamp: January 17, 2024, 01:59:54 am
content: Not sure why you'd want banana to USB leads.. USB is typically always 5V, not something you want to be variable. You can get very inexpensive dedicated USB supplies.As for the other leads, just buy one of the multi-packs that have banana on one end and a variety of clips, hooks, spades etc on the other.

author: radiolistener
author_rank: Super Contributor
timestamp: January 17, 2024, 02:10:14 am
content: Quote from: bizarrefish on January 16, 2024, 11:16:16 pmI'm using these wires with banana jacks for a long time, they are very good and flexible:https://www.aliexpress.com/item/32785850472.htmlQuote from: bizarrefish on January 16, 2024, 11:16:16 pmI didn't seen banana to usb cable which can handle high current, unfortunately there is no such cables, but they are very much in demand for usb power testing with lab PSU.But I found nice XT60 to USB-C cable:https://www.aliexpress.com/item/1005005707951443.htmlit has 20V PD trigger inside, so using it to consume power from USB is limited with 20V mode. But I'm using it in reverse direction to provide power from lab PSU to USB-C. It's not so hard to make XT60 connector to connect it to lab PSU. And it can handle high current, because built for 100W (20V x 5A) usage

author: radiolistener
author_rank: Super Contributor
timestamp: January 17, 2024, 02:18:20 am
content: Quote from: WimWalther on January 17, 2024, 01:59:54 amit is required when I want to measure USB cable, USB power consumption or just to power some device which is powered with USB and consume high current. For example, it is needed when you want to power Raspberry Pi 4 or 5 which has USB-C power input but requires high current about 1-5 Amps. Many usual USB cables just cannot handle it. And it's hard to connect it to lab PSU to measure exact current consumption or voltage drop on cable. This is because usual USB cables and adapters are not compatible with high currents like 1-5 Amps, so they have very high voltage drop and high heating.Some USB devices consume 20 V at 5 Amps from USB-C port which is 100W, most of existing usual USB cables and adapters just unable to handle it. So it's very hard to connect such device to a lab PSU, due to missing cable which can be used for that purpose.This cable works very good for that needs:https://www.aliexpress.com/item/1005005707951443.htmlthe only con is that it has 20V PD trigger, so there is no way to use it to measure USB chargers for 5-15V, because it always request 20V.Also I found nice 100 Watt USB charger:https://www.aliexpress.com/item/1005005281312049.htmlIt can be easy connected to a lab PSU with usual 5.1 power connector and shows voltage and current on it's USB connector.

author: bizarrefish
author_rank: Newbie
timestamp: January 17, 2024, 04:27:00 am
content: Thanks, you’re absolutely right but as I found a lot of posts on PSU’s and great videos I didn’t pose that in my post as it’s down to me to get through the material to make an informed choice. I try and multitask a lot so was posing the leads question to build the thread while I go through my PSU research.Appreciate the advice though, all inline with my expectations on what to get.

author: bizarrefish
author_rank: Newbie
timestamp: January 17, 2024, 04:32:17 am
content: Thanks, my use case for the PSU is both utility and testing and you rightly point out the need to both power and also measure a devices draw.Rather than have various wall worts at the bench I’d rather use a dual or triple psu and simply swap out leads for devices in use and being tested is my thought.

author: tggzzz
author_rank: Super Contributor
timestamp: January 17, 2024, 10:36:43 am
content: Quote from: radiolistener on January 17, 2024, 02:18:20 amWelcome to the forum.For that application, consider purchasing one of the gadgets that you insert between the USB PSU and UUT, e.g.https://www.ebay.co.uk/itm/194913261069You will, of course, need decent USB cables in any caseApart from that...Most test equipment uses 4mm banana sockets, so get stackable 4mm banana to 4mm banana leads.For quick and dirty connections, 4mm banana to croc clip leads are often sufficient.Otherwise just buy what you need for the next project, or chop a 4mm banana lead and attach the relevant connector to the other end.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: January 17, 2024, 01:03:28 pm
content: As already said, a triple supply is nice.Most do not supply more than a few amps though.The meters on most PS are not absolutely accurate and you can put a multimeter on the stackable plugs to check. Or in line for amps.I make my own leads. I prefer Silicone multi strand Flexible wire. You can use Spade terminals at the PS, they get pulled off less often. Bananas are more convenient. Dual Banana are even better, More secure and more convenient. However not all PS fit them. My big PS does not fit dual Bananas. Most Lab PS do fit them.Since I service different radios. I have a few PS Leads already made up and labeled with the manufacturers connection for the specific radio.You can get used connectors and cut and solder wire and then your Bananas.I THINK most leads today are Silicone and that is nice since they are flexible anddon't get damaged by an errant soldering iron.If you make your own, you can have test leads with big and little grabbers and big and little alligator clips or whatever you need.Get wire that is not too big, unless you need big power.Sometimes you can find very good dual stackable bananas on ebay. inexpensively. Use good ones. I prefer Ponoma. The ones with a screw inside that attaches your wire.Since I do RF Stuff, I prefer Linear Supplies. Much less spurious frequency stuff to interfere with measurements.

author: tooki
author_rank: Super Contributor
timestamp: January 17, 2024, 01:49:36 pm
content: Banana to micrograbber, and banana to pin header (“dupont”) male and female.

author: BILLPOD
author_rank: Frequent Contributor
timestamp: January 17, 2024, 02:34:22 pm
content: Take this opportunity to get yourself some new, high-quality DMM test leads and use your old ones for your power supply. You may have to modify them by cutting off the shields on the plug-in end. And on the other end, cut off the probes and solder, (sodder), on stackable bananaplugs that can connect to many things, but usually alligator clips.

author: radiolistener
author_rank: Super Contributor
timestamp: January 17, 2024, 03:00:44 pm
content: Quote from: tggzzz on January 17, 2024, 10:36:43 amit don't worth the money, because it has big measurement error and high voltage drop.This one is better:https://www.aliexpress.com/item/1005004790108378.htmlbut very expensive and still worse than proper DMM:

author: macboy
author_rank: Super Contributor
timestamp: January 17, 2024, 03:20:54 pm
content: I have custom made my own 1, 2, 3, and 4 from your list. My version of 4 has XT60, but same idea. The barrel jack leads I made get used frequently. I simply cut the cord off of some old dead wall warts and put banana connectors on the end. Simple and useful.If you make your own leads, I'd suggest using high strand count silicone insulated wire, as commonly used in R/C which you are familiar with. I typically use 14 gauge, a good compromise among size, flexibility, and low resistance.

author: Jwillis
author_rank: Super Contributor
timestamp: January 17, 2024, 08:51:36 pm
content: Theirs an enormous variety of power supplies on the market. Many of which have 5V USB Type A and/or USB type C ports built in. Those Cleqee cables are really good and come in many configurations. Whats really handy is they work well on DMMs as well. The male banana with alligator clip or test hook types are indispensable for both measurement tool or low current power distribution.

author: alligatorblues
author_rank: Regular Contributor
timestamp: January 17, 2024, 09:19:07 pm
content: Quote from: bizarrefish on January 16, 2024, 11:16:16 pmPSUs do not use test leads. You can use any type of leads for power. You only have to be within 1.0mV. For power you can just buy the leads for $3-$5 Some PSUs have screw terminals on the back. I have a 0-60V 0-15A that I connected to a bus.See which PSU you're going to get, and then decide how to connect it.