Preparatory Notes for ASNT NDT Level III Examination - Ultrasonic Testing, UT

Instrument Circuitry: Pulser-Receiver
The pulser emits the electrical signal that activates the transducer. This
signal, known as the initial pulse, is quite brief, usually lasting only several
nanoseconds (10 -9 , billionths of a second). The output of the initial pulse is in
the order of hundreds of volts; the brief duration provides a fast rise time to
the full voltage. The pulser is connected via output connectors on the
instrument front panel to the transducer cable. The pulser is also connected,
internally, through the receiver circuit, to the display, thus making available
(depending upon the delay setting) a displayed initial pulse signal. This signal
is, of course, present whether or not a transducer is connected to the
instrument. When a transducer is connected, it is in the signal path between
the pulser and the receiver and its output is displayed.