Elcometer 207 Operating Instruction page 8

3.2 THE TRANSDUCER
The transducer transmits and receives the ultrasonic energy or sound waves that the
gauge uses to determine the thickness of the material being measured. The
transducer is connected to the gauge via a cable and a coaxial connector (Microdot
connector).
The transducer must be used correctly in order for the gauge to produce accurate,
reliable measurements. The Elcometer 207 and the Elcometer 207DL operate only
with the 15 MHz precision ultrasonic transducer.
The diagram shows the side view of the 15 MHz, single-element delay line
transducer. The delay line is attached to the transducer with a retainer ring. A drop of
couplant is applied between the delay line and the transducer body to allow the
energy to be coupled in to the delay line. The transducer body has a single crystal element that generates
the ultrasonic energy and this energy is coupled to the material to be measured. The energy passes from
the transducer in to the material. It is reflected from the far wall of the material and coupled back in to the
transducer. The area directly beneath the delay line is that which is measured.
Your gauge is supplied with two replaceable delay lines, 6.35 mm (1/4") and 12.7 mm (1/2"). The 12.7 mm
(1/2") is suitable for most applications and measures steel up to 25 mm. Generally, it should be used to
measure thicker materials. It will also dampen the signal of noisy materials, providing better accuracy.
The 6.35 mm (1/4") delay line provides more signal strength and may allow you to measure tough-to-
penetrate materials.
To change the delay line, unscrew the end of the transducer and apply couplant to the connecting end of
the delay line before screwing together.
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