Method of connecting loads whereby the voltage is additive depending on the number of devices. The most common example is old Christmas light strings, where if one bulb is out the entire string goes out. Most often used in stage lighting to allow four 28V ACL lamps together to run on a 120V supply (4x28=112). In MiniStrips, ten 12V MR16 lamps are wired in series. See also Wiring, Parallel.