I currently work on my ultrasound project. I need to excite my Olympus V305-SU-F tranducer with -100 V spike pulses. Unfortunately Olympus does not provide any kind of datasheet. I know only value of impedance - 50 ohms for resonance frequency (2,25 MHz). My circuit will be powered by DC/DC converter MAX5025.
At first the C1 is beeing charged to Vcc value through R2,R1 and T1 is closed. T1 will conduct after short positive impuls to its base and C1 is discharged into transducer X.
BUT, how can I determine the pulse frequency? Is it given by C1 capacity? So if I want 2,25 MHz pulse I need pulse with duration about 0,44 ns?
In the description of the circuit above, its said, that I need avalanche transistor. Why? I still don´t understand how will the transistor type affect the speed of discharging of C1.