Testing is an important part of the design and production process for any electromechanical device. In addition to understanding the basics of electronics, these devices need to be tested to ensure that electricity is flowing where it should be, and is not where it shouldn’t. With electrical design, designers need to be worried about safety of the user because the voltages and currents can be very high. With electronics, one is really just worried about the safety of the circuitry. The voltages typically aren't high enough to be dangerous. Thankfully, it’s fairly simple to test circuitry if you’re equipped with a little know-how and the right tools. Read on to learn simple ways to conduct electrical testing, and to incorporate this into the overall production process.
Basic testing procedures typically involve anything you can do with a digital multimeter, such as:
- measure voltage
- measure current
- measure resistance
- measure capacitance
- check continuity
Multimeters are typically your first stop on the troubleshooting train. They are useful to diagnose circuitry and to gather simple information like the characteristics mentioned above. Thankfully, they are easy to find, and reasonably cheap. Some other useful tools for basic testing are those that enable you to check power supply (older models are analog; new ones are digital) - these allow you to set a specific voltage and/or current value and operate your circuit at those levels. An outlet monitor is also a good tool to have. They plug into the wall and then you plug your device into it. The monitor will tell you what voltage, current, wattage, etc. you are operating at. This information is good for determining how much it will cost you to operate a given device.
Using & upgrading a basic multimeter for multiple testing points
If you will be testing the same points over and over, you may want to upgrade a basic multimeter...with a rotary switch. They’re fairly banal devices, but they can be utilized to increase your ability to conduct electrical testing. So how might you use a rotary switch? If you have a device with multiple wires (circuits) you will want to ensure that electricity is flowing as you expect. Typically we use a multimeter to perform simple connectivity or continuity tests. A basic multimeter will test a single circuit at a time when the user manually touches the circuit with both ends of the test leads. Want a simple upgrade? Try soldering some multimeter test leads to the common leads on a rotary switch (leaving the male end available to plug into the multimeter). Next, solder the wires for each respective circuit to one of the different positions on the switch. Crimp the other ends of the wires with pins and connect to some type of adapter (such as a Molex connector) that plugs into the device you wish to test. Now all you have to do is manually rotate the knob on the rotary switch and you will get a readout on the multimeter for each one of your test points in turn without having to manually identify the lead wires every time. This is a big time saver.
Want more? You can automate the process using a multiplexer, a data acquisition device (DAQ), and some software (something like Labview and NI Test Stand is a good start for companies that can afford it). A multiplexer is an electronic device that takes multiple input signals and generates a single output signal. In terms of complexity, a rotary switch is at one end of the spectrum, and a multiplexer is at the other. A multiplexer (“mux”) uses software to choose amongst the various inputs. The multiplexer is essentially a chip that fits on a printed circuit board and is typically hard wired to the particular device you are testing through a standard connector. The mux connects to a data acquisition device which plugs into the computer through a USB. The data acquisition device takes various input signals (electrical voltages of various levels) and transforms them into digital signals). This creates a much greater capacity for testing electric circuitry for all kinds of devices.
Creative Mechanisms has experience designing & testing electromechanical components
We’re a design and engineering company with experience across multiple verticals, such as medical devices, toys, industrial design, personal care products, food packaging, and more. While we are not an electrical engineering company, our team has had considerable success devising solutions to problems with electromechanical components, and helping to engineer ideas into reality. To learn more, please visit our blog and resources pages.