Recomendations for a PWM Source - Page 1
Forum section: electronics / testgear

author: mendip_discovery
author_rank: Super Contributor
timestamp: August 11, 2023, 05:10:42 pm
content: I am looking for a portable bit of test gear that is sensibly priced and has a PWM (Power Wave Modulation) output.I have a random eBay item that does it but it's an open circuit board and I could do with something that the customer won't start asking questions of. But at the same time I doubt I could get a Fluke Loop calibrator past the boss.

author: tautech
author_rank: Super Contributor
timestamp: August 11, 2023, 09:21:33 pm
content: Quote from: mendip_discovery on August 11, 2023, 05:10:42 pmNot Pulse Width Modulation ?What's the difference if you don't mind ?

author: Fungus
author_rank: Super Contributor
timestamp: August 12, 2023, 06:16:05 am
content: Quote from: mendip_discovery on August 11, 2023, 05:10:42 pmI don't think that's what PWM stands for.Quote from: mendip_discovery on August 11, 2023, 05:10:42 pmPut it in a box?

author: DavidAlfa
author_rank: Super Contributor
timestamp: August 12, 2023, 06:27:06 am
content: Better detail yorurequirements a bit more. Plain PWM? Closed loop? Modulation input?...This could get as basic as a 555 with a battery, to lots of $$.

author: Fungus
author_rank: Super Contributor
timestamp: August 12, 2023, 06:53:59 am
content: Quote from: DavidAlfa on August 12, 2023, 06:27:06 amOutput frequency, precision, voltage, current...?Quote from: DavidAlfa on August 12, 2023, 06:27:06 amOr an Arduino.

author: mendip_discovery
author_rank: Super Contributor
timestamp: August 12, 2023, 07:40:49 am
content: Quote from: tautech on August 11, 2023, 09:21:33 pmYou are right, pulse width modulation. Not sure where I got power wave modulation from.I have to test a machine that uses PWM as part of its tests. It generates and measures so I am looking for a neat way to do this. It 100 Hz at 50% so nothing special. The customer has a Fluke Loop calibrator but that is >£1000 which just for me to use on 4 machines is a little pricey. We are looking to get a handheld multimeter to do the measurement side of it, Fluke 87 or 287 depending on what we can find, that will at least have a use generally around the lab.

author: DavidAlfa
author_rank: Super Contributor
timestamp: August 12, 2023, 08:13:24 am
content: So the approach would be to manually verify the machine operation when setting different duty cycles, right?These would do it for 5 bucks:https://www.aliexpress.com/item/1005002771032403.htmlhttps://www.aliexpress.com/item/1005004255904120.htmlhttps://www.aliexpress.com/item/1005003352241302.html

author: jpanhalt
author_rank: Super Contributor
timestamp: August 12, 2023, 10:02:40 am
content: If all you need is 50% at 100 Hz, Paisley's compilation of circuits shows a simple way to get that with a 555:http://www.circuitous.ca/LM555.html#23Since the 50% duty cycle is obtained by logic, my understanding is that it is relatively accurate; whereas, the frequency that is dependent on an RC circuit is not so accurate.

author: Aldo22
author_rank: Super Contributor
timestamp: August 12, 2023, 11:28:08 am
content: Quote from: mendip_discovery on August 12, 2023, 07:40:49 amIt's not entirely clear to me what you need.If you just want to generate a square wave at 100Hz, maybe your cheap multimeter will do?An8008for example can do that quite accurately.

author: RAPo
author_rank: Super Contributor
timestamp: August 12, 2023, 12:22:41 pm
content: Buildyour own and put it in a box.Or if you want something fancier, would a fnirsi DSO-TC3 satisfy?Very portable, and has a signal generator scope and component tester

author: mendip_discovery
author_rank: Super Contributor
timestamp: August 12, 2023, 12:52:09 pm
content: Quote from: RAPo on August 12, 2023, 12:22:41 pmI think the DSO-TC3 should do it fine. It's one of them jobs that if I turn up with something home made that I know I will get questions over it. It's a job I have ended up taking on becuase a bunch of cowboys decided they didn't want the job anymore, supposedly they also make multimeters but have to rebrand every few decades. As our firm is local to the job and my boss loves money I get volunteered to do the work, but as cheaply as possible.

author: ledtester
author_rank: Super Contributor
timestamp: August 12, 2023, 06:07:16 pm
content: There's also these signal generators... search aliexpress.com for "SG-003A Signal Generator".https://a.aliexpress.com/_mO0Ng5s