AWG vs. Bench Power Supply - Page 1
Forum section: electronics / beginners

author: ArcticPhoenix0
author_rank: Contributor
timestamp: February 05, 2020, 04:50:46 am
content: Not sure if I understand this but an AWG, specifically the SAG1021 for use with the SDS1104X-E is a way of generating specific waveforms which then excites the DUT which I can then measure the individual components with my scope.After learning that, I ask myself (and now all of you), do I need a bench supply if I have an AWG? Am I missing something here?

author: NDani
author_rank: Contributor
timestamp: February 05, 2020, 07:14:21 am
content: Even though AWGs offer the option to output a DC voltage, this feature is not intended for powering circuits. This is because, as blueskull also points out, AWGs are not designed to source high currents such as several hundred milliamps.Also, most AWGs, including the SAG1021, have a fixed 50 ohm output impedance to match it to systems with 50 ohm transmission lines (in order to avoid signal reflections at high frequencies). This output impedance will cause the voltage of the AWG drop if you try to load it with a high current.So you most certainly need a bench supply as well.

author: tautech
author_rank: Super Contributor
timestamp: February 05, 2020, 07:18:53 am
content: Quote from: ArcticPhoenix0 on February 05, 2020, 04:50:46 amCheck the X-E datasheet and the answer becomes obvious.As it's USB powered only 3V max into 50 ohms is very limiting for a PSU but it could power some low voltage IC's all the same.Also unlike a proper PSU you don't have any current limiting or CC mode.

author: MarkF
author_rank: Super Contributor
timestamp: February 05, 2020, 04:16:17 pm
content: Quote from: ArcticPhoenix0 on February 05, 2020, 04:50:46 amAre you confusing the process of having the scope capture a waveform, transferring that waveform to the AWG, and then have the AWG reproducing that waveform for injecting into a circuit? IMHO, capturing a waveform by a scope to be able to duplicate it by an AWG is a niche capability.You will still need a power supply to power the test circuit. An AWG is not able to do that.A Function Generator creates signals. They are not intended to provide power.

author: GerryR
author_rank: Frequent Contributor
timestamp: February 05, 2020, 04:46:27 pm
content: Or, you could get something like this and have everything in one unit:Tenma 72-7290 Universal Test System DMM Plus Power Supply/counter/generator, Digital Multimeter, Frequency Counter, Function Generator, Power Supply; Triple output power supply; True RMS 40,000 count digital multimeter.Depending upon your level of expertise, this can cover a lot of ground. Of course you still need a 'scope!

author: james_s
author_rank: Super Contributor
timestamp: February 05, 2020, 06:16:04 pm
content: This is kind of like asking if you need a sink since you already have a toilet. They both connect to the water supply and both are typically in the same room but that is where the similarity ends. A bench power supply is essential for almost any lab, most people don't need a AWG or even a basic function generator, it's useful to have but in most cases not really necessary. I have never found a need for AWG myself, I only ever really use sine and square waves.

author: FriedMule
author_rank: Frequent Contributor
timestamp: February 05, 2020, 07:01:49 pm
content: Almost no matter what you want to do, do I recommend to get the right tool for the right job.You can easily use a wrench as a hammer or a screwdriver as a pray bar but they are not build for it. So in other word, use the AWG to create signals and the PSU to create power.

author: ArcticPhoenix0
author_rank: Contributor
timestamp: February 06, 2020, 04:51:46 am
content: Quote from: MarkF on February 05, 2020, 04:16:17 pmFull disclosure; it took me about 2 hours to get a signal from a battery supply, an LED, and a resistor. Clearly no idea what I'm doing here. I'm figuring it out. It's interesting but still mysterious and complex. That's ok because I make my living elsewhere for the moment.

author: james_s
author_rank: Super Contributor
timestamp: February 06, 2020, 05:31:03 pm
content: It sounds like you're probably a year from needing a scope or AWG at all. Put away the fancy toys and spend some time learning the basics. You should know Ohms law and Kirchhoff's laws like the back of your hand and be able to wire up something trivial like an LED to a battery and calculate the required series resistor without any trouble before it makes sense to even touch a scope. Learn the basic principals and spend time becoming proficient with your multimeter, this is absolutely essential to understanding the advanced instruments.

author: not1xor1
author_rank: Frequent Contributor
timestamp: February 06, 2020, 06:25:47 pm
content: Quote from: james_s on February 06, 2020, 05:31:03 pmno expensive equipment may compensate for a lack of basic knowledge

author: ArcticPhoenix0
author_rank: Contributor
timestamp: February 06, 2020, 08:53:50 pm
content: You're very likely correct but I don't expect the fancy toys to fix the stuff for me. I'm mainly trying to get an understanding of what it's able to do and how I should be using it.

author: james_s
author_rank: Super Contributor
timestamp: February 06, 2020, 09:13:28 pm
content: I'm not trying to sound rude but a scope is useless to you until you have a solid understanding of the basics. You may manage to get some wiggly lines on the screen but you will have no clue how to interpret what you are seeing. You don't need an EE degree but at least take some time to become proficient with basic concepts and DC circuits before you tackle AC and situations where a scope is useful. Pick up a copy of The Art of Electronics and read that, it will give you a reasonable foundation without being too heavy.Right now you're trying to figure out how to drive a Ferrari before you've mastered riding a tricycle. You are going to be stumbling around blind until you grasp the basics and it's going to waste a lot of time of people trying to help you. The old saying "learn to walk before you try to run" applies here.

author: ArcticPhoenix0
author_rank: Contributor
timestamp: February 07, 2020, 11:21:36 am
content: I will for sure be getting a copy. I like reading about this stuff.

author: MarkF
author_rank: Super Contributor
timestamp: February 07, 2020, 11:30:52 pm
content: Quote from: ArcticPhoenix0 on February 07, 2020, 11:21:36 amYou can start here:The Art of Electronics 3rd Edition

author: Simon_RL
author_rank: Regular Contributor
timestamp: February 08, 2020, 11:30:02 am
content: Quote from: james_s on February 06, 2020, 09:13:28 pmCouldn't agree more. The Art of Electronics is a must for beginners. Well AOE plus refreshing my maths skills, it is a long time since I did my computer science degree and the maths were nothing compared to electronics.

author: GerryR
author_rank: Frequent Contributor
timestamp: February 08, 2020, 12:22:08 pm
content: I would agree that understanding basics is essential, but.... a multimeter (bench or handheld), a power supply and a reasonably good 'scope will aid in the learning curve. Looking at pictures in a book of a particular circuit, and pictures of the waveforms being generated is one thing, but actually measuring and probing to see actual results is much better. There are plenty of "cookbook" circuits that a beginner can build for fun and learning, and the "basics will become much clearer. And besides you have to start somewhere; I have several instruments that I purchased when starting out that are no longer really useful to me, but I upgraded accordingly as my knowledge expanded.I would say to the OP, don't be discouraged, buy some basic instruments, and have at it. It will be a fun journey!