Electronic load with LED simulation - Page 1
Forum section: electronics / testgear

author: kuon
author_rank: Regular Contributor
timestamp: November 05, 2023, 05:43:02 pm
content: Hello,I am looking for an electronic load capable of simulating a LED, I want to test LED drivers.The features I need are:- Ability to delay current until a threshold voltage is reached- Absolute current and voltage limit for protection, and an indication if this protection was triggeredI found a lot of high end loads with those features, but they are way out of my budget. The only low cost solution I found is Siglent SDL1020X. I am looking for something in the 1k$ range.Do you have any recommendation?

author: DaneLaw
author_rank: Frequent Contributor
timestamp: November 05, 2023, 11:43:38 pm
content: Have you looked at the cheaper programable sink loads from the Far East that cost between 100 bucks to 180?.. brands like Unit-T and EastTesterFor their price, they are often packed in features you usually don't see on cheaper sink loads...? :

author: DaneLaw
author_rank: Frequent Contributor
timestamp: November 05, 2023, 11:46:48 pm
content: Many of the cheaper Chinese versions 42A/420w 1CH ranging from 100 to 180 US (delivered with VAT). do have some aspects of LED test, not sure if that will fulfill your needs and how far you can take it in their PC software or thirdparty software..(sink)bang for the buck, you do get a lot of bang, if sense-wires aint mandatory for your need..LED test.-brief walkthrueslide.https://tinyurl.com/zmrvx3y3Also got a PC control SW with a more extensive test interface, though it would not play along on my unit .

author: kuon
author_rank: Regular Contributor
timestamp: November 06, 2023, 12:51:45 am
content: That's cool. I didn't look into this kind of brand. I know there are some very good things coming out of Chinese factories, but it is very hard to differentiate between quality and bad or even plain scam when the brand is absolutely unknown.I don't have tons of testing to do, but I am hand assembling my driving PCB, and the LED I use are quite expensive and also very bright which is not really comfortable for testing (need glasses...).

author: magic
author_rank: Super Contributor
timestamp: November 08, 2023, 04:53:47 pm
content: Just an idea, if you could test with real LEDs but they are too expensive to risk and the light annoys you, try an equivalent chain of ordinary diodes or those fat 5W zeners or similar stuff.For a larger testing job a DIY load could be assembled from a few opamps and some power transistor(s), but probably not worth it for a one time use.

author: nctnico
author_rank: Super Contributor
timestamp: November 08, 2023, 04:59:09 pm
content: Recently I looked at Tonghui DC loads (also sold as BK Precission) which are advertised to be able to simulate LEDs. OTOH, a general purpose DC load could do as well but likely it needs to be put in constant resistance or constant voltage mode.

author: kuon
author_rank: Regular Contributor
timestamp: November 12, 2023, 01:00:51 am
content: I followed @magic suggestion and I ended up building my own breadboard circuit using diodes with same properties as the LEDs and it works quite well. I also added current and voltage measuring points, if there is no dynamic range requirements it is quite a simple circuit.But I do not have an electronic load and I still would be interested in buying one so I am still open to suggestions.

author: magic
author_rank: Super Contributor
timestamp: November 12, 2023, 09:14:02 am
content: Sometimes simple solutions have to doBTW,Quote from: kuon on November 05, 2023, 05:43:02 pmThis indicator could also be done easily; add a current sense resistor calculated to produce 2.5V at the maximum current and trigger TL431 followed by a simple transistor latching circuit. Maybe even a single NE555 chip could do all of that, if its VCC is regulated.