Not really. That's like saying that all lamps over 300 watts are to be called lamps and those less than 300 watts are to be called light bulbs. A difference between control voltage and switching voltage isn't really a discriminator either.
Is the "condenser" in the ignition of your pre-1980s car not a capacitor, just because the auto mechanic calls it by that name?
There is a difference. Contactors are usually used when driving motors. They have a higher voltage rating to prevent arc-over when stopping a motor. Relays are often used in control circuits and have lower voltage ratings. N.B. There is a voltage rating for the coil that pulls-in the contacts, and a different voltage / current rating for the contacts that drive the load..
The 100% solar-powered airplane Solar Impulse 2 is prepping for its upcoming flight, becoming the first plane to fly around the world without using fuel. It's able to do so because of above-average performance by all of the technologies that go into it, especially materials.
With major product releases coming from big names like Sony, Microsoft, and Samsung, and big investments by companies like Facebook, 2015 could be the year that virtual reality (VR) and augmented reality (AR) finally pop. Here's take a look back at some of the technologies that got us here (for better and worse).
Good engineering designs are those that work in the real world; bad designs are those that don’t. If we agree to set our egos aside and let the real world be our guide, we can resolve nearly any disagreement.
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.