In a series circuit (loads connected in a row end to end), it's easy to calculate total circuit resistance because you simply add up all the resistances to get the total. In a parallel circuit, the voltage is the same across all the loads; the amperage is simply added up, but the resistance is a […]

Friction rate is a value located on a ductulator. We use it during the design phase of a duct system to predict the operating static pressure of a duct system. The challenge with friction rate is that it is often misapplied by folks using a rule of thumb (ROT). In order to apply friction rate properly, […]

Disclaimer: “Ghost voltage” is a term used by techs to explain a phenomenon where they measure voltage they don't expect or when the voltage they see doesn't do the work they expect. More advanced techs know how to use the Lo-Z (low impedance) mode on their voltmeter if it has one to help eliminate this. […]