College student starting my own mini EE lab: are those good starting point gear? - Page 1
Forum section: electronics / testgear

author: technix
author_rank: Super Contributor
timestamp: April 21, 2015, 07:51:36 pm
content: I am a Chinese college student trying to start my own EE lab. I major in CS so EE is, for now, more or less of a dabble actually.The gear I got for now are:A pass-me-down Zhenxing DT-890 3.5 digit DMM (based on ICL7106 chipset, made in the 1980s.)A one-hand-how brand 3.5 digit DMM I bought new in my high school years.A second-hand Luyang YB4325 20MHz CRT oscilloscope with digital readouts (made in early 2000s.)A recent purchase of a unbranded LC meter.Does those seem like a reasonable start point to set up my home lab? I will mostly be either tinkering and researching, if not repairing broken electronics.

author: RoboTechEd
author_rank: Regular Contributor
timestamp: April 21, 2015, 08:14:22 pm
content: Looks to me like you have a great starting point! I would also try to get yourself some type of variable power supply (although for many things an LM317 and some resistors can handle most applications). If you are a CS student, than getting an arduino may help bridge the gap between CS and EE.You also may want to get yourself a small parts collection going so you have what you need when you need it. All of the things below should be pretty cheap online.-An assortment of resistors. You can find diverse resistor kits online pretty cheap.-Assortment of capacitors/diodes-A spool of solid core wire is useful, and a breadboard too for double checking.-Some voltage regulators as stated above (LM317, 7805, etc)-Some OP-AMPS, at least for learning applications-A breadboard! If you don't have one already-Some LEDs, they can be super useful for most projects

author: nctnico
author_rank: Super Contributor
timestamp: April 21, 2015, 11:22:52 pm
content: They want over $500 for that Luyang YB4325I hope you got it for free!Anyway, it seems like a decent bit of kit to start with. I'd also look into LTspice for simulating circuits. It often helps to understand how a circuit works by looking at the current through a circuit and that is easier using a simulator than having to spend $$$ on a current probe.

author: grythumn
author_rank: Contributor
timestamp: April 22, 2015, 04:38:55 pm
content: Quote from: technix on April 21, 2015, 07:51:36 pmA (used?) bench power supply of moderate power might be handy... I'm shopping for one now myself, after getting tired of bodging ones together per project with random wall warts and linear regulators. Useful but not essential.-R C

author: technix
author_rank: Super Contributor
timestamp: April 23, 2015, 11:20:24 am
content: Quote from: RoboTechEd on April 21, 2015, 08:14:22 pmI have a hacked wall-wart-turned-bench-supply capable of max 13.5V at 1A, based on Sharp PQ30RV11 chip.I do have a cache of parts: an assortment of R, C, small stocks of common diodes and transistors, as well as leftover op amps from my PMOS LDO design (and that one can be developed into a very efficient 5A LDO power supply if I want to) I als have a spool of solid core wire as well as some magnetic wire and some inductor making gear.About the power regulator chips, I don't have LM317 or 7805, but I have a small stock of AMS1117-3.3 and AMS1117-5.0 in TO-220 package.I have several breadboards actually, one of them semi-permanently assembled into Arduino-on-breadboard, and another have my PMOS LDO on it.And on the CS-to-EE bridging front, I have several Arduino boards actually, and also several Raspberry Pi which is my personal favorite. Also I have two EPM240 CPLD evaluation boards.

author: technix
author_rank: Super Contributor
timestamp: April 23, 2015, 11:25:18 am
content: Quote from: nctnico on April 21, 2015, 11:22:52 pmSeem to me I got a bargain on that Luyang YB4325 (I got it for CN¥380, about US$60)I still have my school issued NI Multisim, is that good enough? LTSpice always crashes on my MacBook Pro so I am not a fan of it.

author: technix
author_rank: Super Contributor
timestamp: April 23, 2015, 12:08:14 pm
content: Quote from: grythumn on April 22, 2015, 04:38:55 pmWill my hacked wall wart that can push out adjustable voltage a good starting point? It is capable of 13.5V 1A maximum.

author: Muxr
author_rank: Super Contributor
timestamp: April 23, 2015, 01:37:13 pm
content: Quote from: technix on April 23, 2015, 11:25:18 amI've been a fan of Qucs personally:http://qucs.sourceforge.net/

author: RoboTechEd
author_rank: Regular Contributor
timestamp: April 23, 2015, 02:07:16 pm
content: Quote from: technix on April 23, 2015, 11:20:24 amOh wow! You are set then for essentials, in respect tobigtools, you appear to have everything you will need. Good on you! When you have a lab setup be sure to post it in the lab show-off thread

author: grythumn
author_rank: Contributor
timestamp: April 23, 2015, 02:54:29 pm
content: Quote from: technix on April 23, 2015, 12:08:14 pmIt's good for a lot of stuff; 12V, 5V, or 3.3V handles the majority of your digital needs. And 1A is plenty of power to start with. I've made do with something like that for 10 years of tinkering.A dual output bench supply is very useful but not essential.Things to think about:You might want a second rail... say 5v or 3.3V for logic and 12v for relays or an LED string. A second basic power supply should do for this unless you have special requirements.Current limiting... 1A will let the magic smokeout of most devices if you make a wrong connection. I've also melted a few solderless breadboards.You might want a negative rail... some opamps, some old LCD bias voltages. Probably more things I haven't fiddled with.(fairly specialty) You might need HV DC... tubes, etc. Some old VFDs require 20V+. Large series LED strings.Clean(er) power for analog rails... depends a lot on the walwart in question. Switching supplies are fairly noisy, cheap linear ones tend to have significant 50 or 60hz noise.Higher current at lower voltages... a linear won't deliver 1A at ~4V with a 13V source without a LOT of cooling. (Say, testing a high power LED; although you could substitute a beefy power resistor in that case.)-R C(Don't forget about the minimum load; that sharp linear looks like it needs at least 5mA of current through it before it goes into proper regulation.)

author: Lightages
author_rank: Unknown
timestamp: April 23, 2015, 06:38:11 pm
content: Quote from: blueskull on April 23, 2015, 02:38:49 pmReally? Only Fluke makes safe meters? Have you heard of Agilent/Keysight? or Amprobe? or Brymen? Gossen Metrawatt? Hioki? Yokogawa?

author: technix
author_rank: Super Contributor
timestamp: April 24, 2015, 05:00:47 pm
content: Quote from: grythumn on April 23, 2015, 02:54:29 pmAbout the current limiting, will a 300mA LED constant current source work?And about the HV rail, will a DC-DC boost module (36V/1A max) work?

author: technix
author_rank: Super Contributor
timestamp: April 24, 2015, 05:08:24 pm
content: Quote from: blueskull on April 23, 2015, 02:38:49 pmI don't have that much a budget (CNY 500-600) so no. The CRO serves me well enough for now and if I need to single shot (usually for digital bus stuff) I go one layer up and use the CPLD eval kit or an Arduino to capture the bus traffic directly.I have a hacked wall wart turned bench supply and that will work for me, for now at least. I may need a function generator (spotted a used one for CNY 120 as well but yet to buy it)Also I don't tackle anything over 40V so no Fluke for now maybe.

author: technix
author_rank: Super Contributor
timestamp: April 24, 2015, 05:14:55 pm
content: Quote from: Lightages on April 23, 2015, 06:38:11 pmFluke, Agilent, I know those, but too expensive for me. Amprobe? or Brymen? Gossen Metrawatt? Hioki? Yokogawa? What are those??? I have never heard of those here in China.

author: technix
author_rank: Super Contributor
timestamp: April 24, 2015, 07:49:35 pm
content: Quote from: blueskull on April 24, 2015, 07:33:55 pmIf you would like to donate a Fluke one I would appreciate, but since my late 80's Zhenxing pass-me-down meter worked well enough I would not spend money on buying one just yet.

author: retiredcaps
author_rank: Super Contributor
timestamp: April 25, 2015, 06:25:07 am
content: Quote from: technix on April 24, 2015, 05:14:55 pmThose are all quality name brand manufacturers of multimeters. Depending on how much research you have done, your interest in electronics and certainly demographics, country, experience, etc, I'm not surprised you have never heard of them.Just like I live in Canada and have probably never heard of many Chinese companies.If you stay active on eevblog, you will get to know the names soon enough.