ultrasonic transmitter cable 2

[GoKid]

Hi folks,

I want to send 150v 0.4amp to a remote ultrasonic transducer that has 200 ohm impedance. The NPN driving ciruitry will be about 3-4' from the transducer housing. Digital circuitry will be nearby. What specific brand name/type cable would one recommend - it may bump or rub up against the operator. I was thinking about using in-wall audio speaker cable.

 

[VEBill]

"...150v 0.4amp ... 200 ohm impedance..."

150/200 is 0.75A.

Cable probably not critical, but the operator should not be anywhere near 100 watts of audio, even if ultrasonic.

 

[logbook]

50 ohm coax will probably do because the cable length is very short compared to the wavelength.

 

[GoKid]

Current source to transducer is only 0.4a. Transducer can't draw more than what's available. Sounds like I am making an ultrasonic weapon more than a transmitter by your concern. I will ponder your concerns. Thanks for both replies.

GoKid!

 

[itsmoked]

Yeah I'm wondering too.. What about the TIG welder next to me that is packing 8.2kW of square-wave.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[VEBill]

"TIG welder"

To make sure it's clear: I'm more worried about the operators ears (100 watts of audio, even if ultrasonic) than his elbows (high voltage/power in a cable).

 

[itsmoked]

Ah ears... That makes sense. We thought you were referring to the electrical energy.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[TurboXS]

A few things to consider.

1. Transducer driving signals can be either a continuous signal or a pulsed signal. You may need to consider the effect the cable has the shape of the signal, particularly with sharp pulse envelopes.

2. Ultrasonic transducers are generally a capacitive load so the capacitance of the cable is important as it acts like a voltage divider.

 

[GoKid]

Its a single 40KHz wave repeated every 10ms.

 

[nbucska]

The power transducer is usually driven with its resonance
frequency - in this case you can't generate a single
wave for it will not reach a significant amplitude and
it will ring for time depending on the Q.

Plesae read FAQ240-1032
My WEB: <

http://geocities.com/nbucska/>