Ultrasound equipment : the device which transmits the sound into patient and detects the echoes that called the transducer.
The transducer means a device that converts one form of energy into another . The primary component of the transducer is piezo-electric crystal which enables the conversion of electrical pulses into mechanical energy (sound) and convert sound to electrical signals.
Most ultrasound equipment now uses pulsed sound . Which means that a voltage is applied to the crystal for a fraction of second. this distorts the crystal and a pulse of ultrasound is therefore produced. The crystal will then relax while it is waiting to receive a returning echo . Only 1% of the operating time is spent by the transducer transmitting sound , whereas 99% is spent listening for echoes . echoes detected by the transducer give rise to very small voltage signals in the piezoelectric crystal . By measuring the time it takes for an echo to arrive back at the transducer, the depth of the echo can be calculated by the equipment.

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