DSO selection for seconday school course - Page 1
Forum section: electronics / testgear

author: bjbb
author_rank: Contributor
timestamp: August 08, 2021, 10:43:34 pm
content: Myself, and other engineers, teach an embedded systems course at a local parochial school. Previously we had used either the chemistry or the physics lab because the six week course was during the summer only, and now it will be a full semester during the normal school year, perhaps 2x per school year.The school built a separate electronics lab. And the administration is thinking about adding a vocational repair course to 'use up' available lab time, but that is not my mandate or my concern as I am not qualified to teach such a course and do not have the time available to write a course - so test equipment requirements for vocational stuff was not considered by our T/E selection.Assuming we have two instructors available, the class is limited to 14 students. There will be two students per bench, but we do have 9 benches + bench on instructor's platform. So we are buying 10 sets of test instruments, where one or two will be spares. The DVM, sig gen, and power source have been chosen and bought. Actually we made the 10 DC power supplies because the cheap off-the-shelf stuff has always been the problem child during the last 15 years.The DSO selection remains, and we have 3200 USD remaining in the budget; and we are arguing about it. Some other instructors (mostly code weenies) want MSOs with 100MHz analog for both channels. The scope (pun not intended) of the projects and the curricula for the previous 15 years do not justify any more scope capabilities. These are high school kids, so if they get into a design and test hole, myself or another instructor can bring in our personal scopes. I am looking a the GDS 1072 or 1102, and buying some cheap 'disposable' logic analyzers. My main concern is the robustness of this scope and the probes.Any counter suggestions?

author: nctnico
author_rank: Super Contributor
timestamp: August 08, 2021, 10:55:42 pm
content: I'd get 4 channel scopes so the scopes can also do a decent job for working on microcontroller projects. The GW Instek GDS1054B is about the cheapest model at the moment with mature firmware and modern features (such as deep FFT and protocol decoding). (for example:https://www.tequipment.net/Instek/GDS-1054B/Digital-Oscilloscopes/?v=0)You can get an educational discount as well so it might just fit the budget. This one can be upgraded 'for free' to 100MHz using a simple key generator.Personally I consider regular probes to be disposables; they are subject to wear. Perhaps the best idea is to get new probes every year so students aren't fooled by problems due to the probes being worn out. Decent probes can be bought in bulk from China (Aliexpress for example) for low prices.

author: Tony_G
author_rank: Super Contributor
timestamp: August 09, 2021, 12:14:56 am
content: Nctnico is completely correct in my view - Get the cheapest decoding 4 ch scope you can and it'll be good enough for the course - I think back to my time at university and I can't think of a course that I took in the first 2 years that needed more than the basic DZ1054Z I have on the bench (seriously this is the one I use 95% of the time and I only go to my Tek/HPAK scopes when I know I need better readings). I also agree that probers should be considered a wear item to be replaced.

author: Fungus
author_rank: Super Contributor
timestamp: August 09, 2021, 02:44:36 am
content: You're in the USA, you've got $320 per 'scope, there's only one choice:https://www.tequipment.net/Instek/GDS-1054B/Digital-Oscilloscopes/?search=trueLuckily it's a good one. Those are great little 'scopes.

author: TK
author_rank: Super Contributor
timestamp: August 09, 2021, 03:45:17 am
content: +1 for GDS1054B. Use education discount and/or EEVBLOG discount code and sales tax exempt certificate + free shipping and each scope should cost less than $300

author: Kleinstein
author_rank: Super Contributor
timestamp: August 09, 2021, 07:59:40 am
content: For most tasks 50 MHz is sufficient bandwidth. To really look at the edges of digital signals and ringing it may take more BW. One could consider having not all the scopes with 4 channels, but 1 or 2 faster (e.g. 100 or 200 MHz) ones with 2 channels, so if needed at least the instructor can show those very fast effects. It anyway needs some care with the probe to make full use of 100 or 200 MHz BW.The probes (actually the ends of the cables) wear out and may fail. For normal scholl use they may still last many years. Most of the time only 1 or 2 probes would be used, so half the probes would not be used very often.