EE 333 : Home lab bench buying list

Equipment for an electronics bench at home.

"Setting up a lab" videos: From EEVBlog. This is a bit more focused on soldering irons and peripherals, but that is OK. He has a follow-up that proposes a lab for $300, but I think he is cutting corners too much here.

Note: Prices listed below are from Aug. 2020. Availability of specific items and prices are likely to be different now.

Oscilloscopes

Digital multimeter (DMM)

Considerations

Handheld / benchtop. Handheld DMMs are more portable and less expensive. Benchtop DMMs have higher accuracy and are more expensive.
Precision. Usually denoted in "digits". Most handheld models are "three and a half" digits and a typical benchtop might be "six and a half" digits. As an example, if you were measuring a 1.5-V battery, the handheld would be accurate to about 10 mV while the benchtop would be accurate to about 10 μV.
Standard features. Every DMM should be able to measure DC/AC voltages, measure resistance, and provide for continuity checking. Most will also be able to measure DC/AC current. Any multimeter you purchase should be able to do at least these 6 functions.
Autoranging. Some meters can find the correct range for the measurement. Others require that you set a switch for the range. Autoranging is preferred, because it requires less "switch flipping". A lack of auto-ranging is not a necessarily a deal breaker, but it will require that you spend extra time putting the meter into the correct range for each measurement.
Extra features. Some handheld meters offer diode testing, capacitance measurements, frequency measurement, temperature measurements, and even transistor measurements. These are nice, but not essential.
Frequency response. If you want to use the meter to do frequency response measurements, check the frequency limit for the AC voltage measurement. For cheaper meters, this can surprisingly low (tens of kilohertz) and would limit the usefulness for higher signal work.

Videos

EEVBlog with advice on buying a multimeter The video is 10 years old, so the specific models may no longer exist, but the advice is still good.
A somewhat useful review of a few meters.
Tons of multimeter reviews from MJ Lorton. If you can wade through it all.

Some DMMs to consider

The list below includes only hand-held meters. Bench-top models are quite expensive (> $1000) and probably overkill for a first home bench set up. There are are hundreds of hand-held DMMs to choose from, and many of those will be perfectly suitable for class lab work. Whichever you get, make sure it has the basic functions (V, I, R). Don't go too cheap! ($10 is too cheap.) If price is concern, buy a mid-range model now, and then get a better model when you have real job. There is nothing wrong with having more than one DMM. (I have a half dozen myself.)

Fluke 115. $199. This might last you a lifetime. The 117 model is very similar.
Keysight U1232A $173.
Extech EX330 $66.
Mastech 8268 (approx. $40 at Amazon). I have this one and I like it.
AstroAI DM6000AR $35.

For comparison, the class labs have the Keysight 34461 bench-top DMM which lists for $1175.

DC power supply

This is one place where people are inclined to cut some corners. It seems that it would be easy to use some batteries or an old phone charger as a make-shift power supply. This is usually a bad idea. Often we need +/- supplies for amps. Often we need voltages other than what the batteries or charger can provide. Often we need more current than can be supplied from a battery or simple charger. There is really no substitute for having two or three good quality power supplies at your bench. A single-unit triple-output supply like we use in the class labs works well and is very convenient. They cost a bit more, but are probably worth the price. However, there is some possibility for corner-cutting. It is not hard to design a decent DC power supply. In fact, we will learn how to do exactly that in EE 333. For around $50, we could make a reasonable triple-out supply that works well enough for most beginner-type projects — certainly much better than a collection of old batteries or a random DC wall plug unit. Stay tuned in 333. Or, if you are in a hurry, choose the triple-output supply project and come see GT to get started.

Considerations

Voltage range and max current. You probably would like to have one positive supply that can be varied between 0 and 25 V, one negative supply that vaires between 0 and -25 V, and a third supply that can be varied between 0 and 6 V (or so.) For class work, a current output of at least 1 A for each supply would probably be adequate. For bigger projects 2 A or more might be desirable.
Regulation. Any decent supply will have good regulation (less than 1%).
Precision. How precise (to how many decimals points) can the output voltage be reliably set.
Readout. A digital readout would be typical. An analog meter is probably acceptable. Even without a readout, you can probably adjust voltages using your DMM to measure voltages.
Plus/minus tracking. Some supplies have the positive and negative supplies matched to track, so that the magnitude of the postive and negative are always the same. It is convenient if you always use matched +/- supplies for amplifiers. But tracking is definitely not a "must-have" feature.
Interfaces. Higher-end supplies might have capability for interfacing with a computer, allowing for measurement automation.

Videos

The KIss Analog guy shambles through a description of triple supplies.
A nice overview from Element 14.
Another overview from Keysight. (I could do without the dorkiness at the beginning.)

Some triple output supplies to consider

There is a wide range of supplies from many different companies. Keysight and Tektronix have very good supplies, but they are quite expensive. There are relatively few inexpensive supplies that have three variable outputs. Many companies have supplies with two variable outputs and one fixed (usually at 5 V). This may be OK. Also, don't exclude the possibility of "mixing and matching". Some companies offer inexpensive single and dual supplies. Buying three cheaper single supplies could be a way of making an inexpensive three-supply set up.

Siglent SPD3303C. List at $289. Note that third supply is not truly variable, but only selectable to 2.5 V, 3.3 V or 5 V.
Rigol DP831A. List at $473.
Tekpower They have one triple-output supply that is a knock-off of the Keysight supply used in our lab and is quite expensive. That have a second model, the TP3005D-3 that lists for $240. However, the third supply is fixed at 5 V, not variable. In addition, they have wide range of other supplies that could could be used to set up power supply suite. For example, you could use three of the single-supply model TP3005N (0 - 30 V, 0 - 5 A, $60) to make a flexible triple supply set up.
Korad 3305. List for $250 at Amazon. Note that the third output is fixed at 5 V, not adjustable. I have not used any Korad products, and the quality of their web site and documentation give me pause. But it is a low price, and there are reviews that claim that this is a decent product.
Elenco makes a kit power supply that lists for about $80 at Amazon. It has adjustable ±15 V supplies, a fixed 5-V supply, and even a 12-V AC output. It's not ideal, but it is inexpensive and might be OK for a starter supply. (A primary business for Elenco is making educational lab supplies and kits.)

For comparison, the class labs have the Keysight E3630 triple-output supply which lists for $1341.

Function generator

This is another place where you might save some money by using some homebrew. There are many kits — like this one from SparkFun — that allow you to generate signals on the cheap. (One of our 333 "first" projects is a simple, audio-frequency function generator.) You might also be able to find a phone or computer app that will generate voltages through the audio jack. However, I would also be cautious in using "short-cut" approachs. I would always (Always!) measure the input signal as well as the output. It is too easy for the source to become distorted in some fashion. Also, if using a phone or computer app, be very careful about connecting your expensive devices into a circuit under test at the lab bench. More than a few people (including me) have damages output ports or fried logic boards, to obvious consternation. You should always have a buffer between your phone/computer and the circuit in order to protect your stuff.

Considerations

Frequency range. A 1-MHz upper limit would probably be OK for class use. Most units will probably have a range starting below 1 Hz and extending to 10 MHz or more.
Available waveforms. At a bare minimum, the generator should be able to do sine, square, and ramp (triangle).
Arbitrary waveforms and modulation. Not essential, but it is definitely nice to have the ability to create other typs of waveforms.
Output amplitude. Output level should be at least one volt peak-to-peak. And several volts peak-to-peak would be better.
Frequency precision.
Amplitude precision.
Output resistance. Many generators have a Thevenin resistance of 50 &Ohm;s. If the output resistance is bigger, there will a larger voltage divider effect.
Interfaces. Higher-end models might have capability for interfacing with a computer, allowing for measurement automation.

Videos

The quick-and-dirty Afrotechmods treatment.
Siglent vs. Rigol shoot out.
A tutorial from an actual class. (Washington State Univ.)
$7 vs. $107 function generator from GreatScott!.

Some function generators to consider

As usual, Keysight and Tektronix have excellent function generators, but they are quite expensive for beginner's set up. Below are some less expensive units that would still be very good.

Siglent 800 or 1000 series. The Siglent SDG810 lists for $239.
Rigol 800 or 1000 series. The Rigol DG811 lists for $279.
Koolertron The two-channel 15-MHz generator is $100 at Amazon.
B&K Precision. The model 4003A lists for $300.

Soldering iron