| T O P I C R E V I E W |
| Patritech |
Posted - Jul 28 2009 : 3:19:03 PM
Hi everyone.
There was a problem with the document I posted yesterday. I believe I've fixed the problem.
What I have posted here is a document that I created so that people can learn to transmit and receive data using ultrasonic transducers. I also customized my circuit so what every time I sent a transmission, the receiver circuit toggled. If you have a look, you'll see what I mean. I hope you all enjoy it =) Follow the link below.
www.electroniclessons.com/ultrasonictransducer.wps.doc |
| 3 L A T E S T R E P L I E S (Newest First) |
| Patritech |
Posted - Jul 28 2009 : 8:59:42 PM
Thank you for the kind critique, Mister Guru. You are right, the gain is 20 when pins 1 and 8 are left open. A minor Typo. I chose the LM386 because they cost pennies, and that's what the idea is here. The potentiometer is used to set the voltage at the negative input above the ambient noise level so that the output stays at 0v until a signal is being transmitted. The bottom line is that it works, and it is meant to do nothing more than to help those who are interested in learning about how to play with transducers. As stated in the document, it is hardly the best design, but it is simple, and easy to manipulate. Discrete amplifiers work much better, but require a lot more work, and a substantial amount of passive components. |
| audioguru |
Posted - Jul 28 2009 : 6:52:34 PM
There are errors:
1) The gain of an LM386 is 20, not 50. A low noise wideband audio opamp should be used instead of the noisy LM386s.
2) The second LM386 should have a capacitor to boost its gain to 200 instead of a piece of wire.
4) The pot feeding voltage into the (-) input of the second LM386 does not make its output go from 0V to +5V. It goes from +1.0V to only +2.5V and the pot is very sensitive. |
| pebe |
Posted - Jul 28 2009 : 5:26:23 PM
My Internet Explorer can't display the page. |
|
|
