Mechanical fire alarm horns - DC vs FWR sound demo скачать в хорошем качестве

Mechanical fire alarm horns - DC vs FWR sound demo

FWR, or Full Wave Rectified current is often outputted by cheaper fire alarm panels, including my Edwards Fireshield Plus. DC, also known as Filtered DC is most outputted by higher end panels, such as my Potter PFC-6006. It's also what comes out of batteries. While DC is a constant output of electricity, FWR is essentially just AC, but all the negative voltage is converted to positive voltage. This means FWR is basically 60 pulses of electricity per second, as opposed to a constant current flow. While the difference is indistinguishable in most applications, when it comes to old mechanical horns, it can cause them to sound scratchy in comparison to how they'd sound on DC.