The Smith Meter Model PA-11 Preamplifier is designed to be a replacement for the Waugh PA-11 preamplifier.  It can be used with Smith Meter Turbine Meters or can  be field mounted. It is used to convert a low voltage  sinusoidal signal to a square wave pulse form that can  be used to increase the transmission distance of the pulse or convert the pulse form for instruments that require a high speed, edged-triggered input. The preamplifier has also been designed with a jumper-selectable gain that can be used to either increase or decrease the sensitivity of the unit to fit the needs of the application. The preamplifier has the capacity to operate with either two or three wires. On the two-wire system, the output signal and power are carried on the same two wires