The Electronics Test Bench: Basic, Better, Best
By Rudy Ramos, Mouser Electronics
Whether you are designing new products for a large corporation, tinkering with electronics as a hobby, or working somewhere in between, having the right test equipment for your needs is essential. Test benches are often seeded with equipment that’s been handed down from generation to generation (which is a testament to those manufacturers, indeed) or shared among multiple departments at a company. That said, the proper test equipment is not necessarily—or even often—the most expensive or the most fully-featured. Instead, the right test equipment depends on your level of electronics experience and testing needs.
In this article, we will examine the following core pieces of test bench equipment, outline considerations for purchasing equipment that meets your needs, and explore how test bench equipment evolves as skills and requirements become more advanced:
- Multimeters: Used to check continuity, resistance, voltage (V), VDC output, and low direct current (DC), among other measurements
- Power supplies: Used as a reliable source of DC power for developing and testing circuits under a variety of conditions
- Soldering stations: Used to create circuits by connecting electronics components
- Oscilloscopes: Used to measure change in electrical signal over time, which yields various data, including amplitude, frequency, rise time, distortion, and noise, among other parameters
- Accessories: Used to keep you safe and make testing easier
The Basic Test Bench
Figure 1: More often than not, a basic electronic bench setup can prove to be sufficient for making most printed circuit board repairs. (Source:vgajic/Getty Images)
The basic test bench is ideal for high school and college students, hobbyists, and tinkerers who dabble in an infinite number of possible electronics applications, ranging from audio and communications to robotics and wireless…and a multitude of applications in between. For these enthusiasts, the right equipment should not only meet testing needs, but also be easy to use and not create obstacles that impede progress.
Multimeter
The multimeter, also known as VOM (Volt-Ohm-Milliammeter), is the most basic tool on your electronic bench, so choosing one that meets your test needs, is accurate, and is easy to use is key. For a basic test bench, handheld digital multimeters (DMMs) offer several benefits:
- They provide portability and accuracy at an affordable price.
- They are easier to read, do not require calculating exact value, and have no moving parts that eventually wear and tear.
- They are more accurate than their analog counterparts because they are free from parallax error (i.e., the perceived shift in an object's position when viewed from different points).
Other aspects to consider when choosing a handheld DMM:
- The resolution and number of display digits.
- The capability to measure true RMS (Root Mean Square) volts, which accurately measure pure and complex wave forms.
- The capability to measure temperature.
These DMMs from Extech and Fluke are examples of handheld digital models ideal for the basic test bench:
Power Supply
Suppose you plan to power up any maker board or want to provide power to your newly designed circuit. In that case, you need a reliable source of DC power for developing and testing circuits under various conditions. We recommend a switch-mode DC power supply (SMPS) for the basic test bench, which uses a switching regulator to control the electrical power conversion from AC to DC. Although SMPSs tend to generate high-frequency noise that can affect surrounding sensitive electronics, SMPSs offer key benefits for basic test bench needs:
- They're lighter and more compact than linear power supplies.
- Their efficiency ratings are higher, so they run cooler than their linear counterparts.
A variable voltage model with an upper range of 10A and 30V ensures you have enough current capacity to meet a variety of needs.
These DC power supplies from B&K Precision and Global Specialties are good examples:
Soldering Station
A basic soldering station should, at a minimum, include the power unit, soldering pencil, stand, and sponge. In choosing a soldering station for your basic bench, look for one with variable temperature controls up to 450-550 degrees Celsius to meet most needs. Analog temperature control is adequate for most bench soldering, but a digital soldering station provides you with extremely high-precision temperature control. This 70W WE Digital Soldering Station from the Apex Tool Group is ideal for a basic test bench.
Oscilloscope
Students, hobbyists, and tinkerers often find that a handheld digital multimeter is all they need for testing circuits. However, when these requirements begin to include troubleshooting, debugging, or diagnosing circuits or working with signals that involve buses, pulse signals, or fast circuits, then an oscilloscope (or O-scope) might also be needed. An oscilloscope measures electrical signal changes over time; those measurements are displayed as different types of waveforms that yield various data, including amplitude, frequency, rise time, distortion, and noise, among other electrical parameters.
Compared to other essential test bench equipment, oscilloscopes tend to be expensive, so you may not want to invest in one until you need to troubleshoot—not just measure—circuits.
In general, we recommend selecting a portable model, such as the B&K Precision 2190E or Seeed Studio DSCope U3P100. Both pocket-size oscilloscopes are easy-to-use, low-cost options that pack powerful performance to help engineering students, hobbyists, or electronics enthusiasts debug and analyze their circuits.
Accessories
Practical accessories for a basic test bench include an electrostatic mat and a wrist strap, which ground you and prevent component damage due to electrostatic discharge. Additionally, hand tools such as wire cutters and strippers, crimpers, screwdrivers, and tweezers are indispensable when testing electronics.
Mid-Range Test Benches
Intermediate users might include educators, advancing students and hobbyists, as well as maintenance and repair professionals who build, troubleshoot, and fix electronics. In general, their test bench needs require more input/outputs, higher power/wattage, additional features, and products that are easy to set up, use, and monitor but that are robust enough to take care of the most demanding measurement needs. Mid-range test benches may also include equipment that is specific to an application or technology area.
Multimeters
Mid-Range multimeters have:
- Better resolution and more display digits
- Dual Displays
- Capabilities to measure frequency, period, statistics, histograms, and more
Mid-range multimeters, such as Keysight's EDU34450A/120 Digital Multimeter, combine high performance, durability, dependability, ease of use, and VDC accuracy. It is recommended that these mid-level benchtop multimeters be calibrated at regular intervals, preferably yearly.
Power Supplies
When choosing a power supply for your mid-level test bench, consider the types of tests you will be doing. For example:
- Do you need constant current and voltage, variable current and voltage, or both?
- Do you need a programmable power supply for manually setting output?
- Do you need a linear power supply for signal processing, data acquisition, and control circuit testing?
- Do you need an uninterruptable power supply (UPS) to help prevent interruptions in power?
- Do you need two separate power supplies to run both low voltage-low current and high voltage-high current tests?
These power supplies from Teledyne LeCroy are good examples of mid-range power supplies:
Soldering Stations
A mid-range soldering station has additional features and capabilities that enhance the soldering station's performance and efficiency. These might include a graphic LC display, a fume extraction unit, solder tool recognition, heating plates, the capability to update the station's firmware, and automatic standby mode, to name a few. The Apex Tool Group WT1 and WT1H Soldering Stations are excellent examples of a mid-range soldering station.
Oscilloscope
The biggest differences between basic and mid-range oscilloscopes are bandwidth and rise time (edge speeds). Whereas basic o-scopes have maximum bandwidths of less than 100MHz, mid-range models might have a maximum bandwidth of 500MHz. Increased rise time (edge speeds) capabilities help users more accurately measure pulses and steps like those found in timing signals, where accurate rise time measurements are critical to their design requirements. These oscilloscopes from Teledyne and Keysight are good examples of mid-range oscilloscopes:
Accessories
Practical accessories for the mid-range test bench include:
- A solder fume extractor, which promotes health and safety by extracting lead-based solder fumes and smoke using either HEPA or activated carbon filtration.
- A ring magnifier lamp, which makes small components easier to see and reduces fatigue.
- A precision vice, which frees your hands from holding components while trying to work on them.
These products from Jonard Industries, Aven Tools, and PanaVise are good examples of useful accessories for the mid-range test bench:
Top-End Test Benches
Figure 2: High-end oscilloscopes allow electrical design engineers to probe deep into their circuit design and conduct a detailed analysis of elusive electrical signals. (Source: ilbusca/Getty Images)
Top-end test benches are used by design engineers, certified electronics professionals, and electronics professionals working with standards. Test benches for this group of professionals include equipment that's both calibrated regularly and specialized to support their application. Whereas we saw mid-range test equipment gain features, inputs, and outputs for high-volume and multiple uses, equipment for this high-end group tends to have fewer, dedicated features and instead focuses on the highest precision available and specialized applications. Examples of this high-end electronic test equipment include:
Conclusion
Regardless of whether you are a seasoned engineer or an electronics amateur testing your first simple circuit design, your bench test equipment should be customized to your testing needs to ensure optimal results and experiences. Equipment such as multimeters, power supplies, soldering stations, and oscilloscopes are essential for testing. Test bench equipment's specific capabilities and features vary from minimal capabilities at the fundamental level to multi-capability and multi-function at the midpoint and then go down to fewer, more specific capabilities and functions at the high end. Choosing bench test equipment involves considering your current needs and budget, as well as how your needs may change in the future.
Rudy Ramos is the project manager for the
Technical Content Marketing team at Mouser Electronics. He holds an MBA from Keller Graduate School of Management
and has over 30 years of professional, technical and managerial experience managing complex, time critical projects
and programs in various industries including semiconductor, marketing, manufacturing, and military. Previously, Rudy
worked for National Semiconductor, Texas Instruments and his entrepreneurial silk screening business.
