A while back, I had a tech who was having some trouble finding a 35 PSI (2.41 bar) make-on-fall pressure switch. One adjustable switch in the catalog said (SPDT), but he didn't quite understand what that meant. In that case, it means single-pole, double-throw, and the “double-throw” part means that the switch has terminals in both the […]

If you've ever sat close to a bonfire on a really cold night, you may have noticed that your face starts to get really warm. The minute you put your hands up and shield your face from the light of the flame, your face cools off almost immediately. That happens because the flame is heating […]

In HVAC and electrical school, one of the first things you learn about electricity is Ohm's law: Volts (V) = Amps (I) x Ohms (R) Pretty simple, right? Watt's law is just as easy: Watts (P) = Volts (E) x Amps (I) With this newfound knowledge, the student walks confidently into the real world with […]