Search results

  1. zgnoh

    again, microphone input high school project

    thzzz, rili sorry for repeatedly making silly english mistakes... English is not my mother tongue leeeeeeee... "earthed" ;D, it should be "grounded" :-* So now we have both variable voltage-gain pre-amplifier and the variable volume control. Both accounts for the sensitivity or setting of the...
  2. zgnoh

    again, microphone input high school project

    I will connect pin 9 to pin 3 for bar mode ;D thanks very much for your help ar, :) I have some questions about your diagram 1) Is the word "Rectifier" supposed to be under the diode and capacitor, and the word "Preamplifier" be under the transistor and resistors? 2) There is just one input for...
  3. zgnoh

    again, microphone input high school project

    I just put P.22 of the factsheet http://www.alltronics.com/download/LM3915.pdf#search='LM3915' in the written part of my project. replacing the word "LOUDSPEAKER" by "MIC INPUT", the word "Output Amplifier" changed to "Amplifier and Rectifier(+filter)" is it okay!? leaving the details of...
  4. zgnoh

    again, microphone input high school project

    thanks, I have some problems drafting the circuit regarding LM3915 just silly problems. http://www.national.com/ds/LM/LM3915.pdf according to page ten of this factsheet FIGURE 1, the amplifier and rectifier. the input,,, only one input...>!?!?!?!..<<??!? how can I connect a microphone...
  5. zgnoh

    again, microphone input high school project

    thanks~ where can I find the LM3915 datasheet? I'll have to do the written part of the project, I'll be using the diagram below to briefly illustrate the flow of the circuit: Click here, circuit Then in practice, I'll use the IC, do some calculations on the values of capacitance, resistors. Do...
  6. zgnoh

    again, microphone input high school project

    then do I have to use a specially designed rectifier? moreover, as I mentioned in the last reply, u have a brief idea of my project. but will the rectifier give a very smooth DC even the amplitude is varying? thanks vy much. bed time~
  7. zgnoh

    again, microphone input high school project

    Thanks vy much again. Perhaps it'll take me some time to digest :-* I'm doing a project trying to control the switches so that there'll be some kinda musical fountain with a music input from a CD. A microphone version is for demonstration. when people sing with the microphone,,, switches open...
  8. zgnoh

    again, microphone input high school project

    Thank you very much. i've been wanting to know the voltage generated by speaking to a microphone!!!~ I still have a few problems: 1) why do I not have to use the bridge rectifier but a single rectifier diode instead?~ 2) Should I use a PreAmp before the rectifier? Would it make the circuit not...
  9. zgnoh

    again, microphone input high school project

    Circuit Diagram Here sorry again,,, I know I've been quite weak at electronics. About the circuit diagram: Input from Microphone -> Retifier/Filter Circuit to convert the input wave to steady direct current of voltage similar to amplitude of wave -> Variable Resistor -> Potentiometer...
  10. zgnoh

    Please comment on my project >< thanks~

    this is what I mean filter circuit Voltage Follower
  11. zgnoh

    Please comment on my project >< thanks~

    thanks, yes you're right. IF the amplitude of sound exceeds a certain level, it activates an electromagnetic relay. I have several questions: 1) Is Voltage Follower = two "not gates" used in conjuction? 2) Do I have to amplify the amplitude of sound so that the voltage is large enough? 3) Is...
  12. zgnoh

    Please comment on my project >< thanks~

  13. zgnoh

    Please comment on my project >< thanks~

    The link is okay now :'(,,, pls help me. thanks :-*
  14. zgnoh

    Please comment on my project >< thanks~

    I'm very sorry,,, can you open a new browser and paste the link to see it... I don't know why it is like this too&gt;&lt;
  15. zgnoh

    Please comment on my project >< thanks~

    oh, sorry, if you don't see the diagram, open a new browser and paste the link there &gt;&lt;
  16. zgnoh

    Please comment on my project >< thanks~

    There is an input current from a CD or a microphone. Then if the amplitude of the sound exceeds a certain level, it activates the switch opening circuit to open a switch. The circuit diagram is here, pls click. Is there any mistakes/flaws with the circuit? moreover, is the "Voltage Follower"...
  17. zgnoh

    How to use a PID circuit to regulate temp.?

    Thanks very much. Also thanks for redirecting ;D In case i have any other/further problem. May I ask for help? I don't know how to use the PID, how to connect it with other stuffs?
  18. zgnoh

    How to use a PID circuit to regulate temp.?

    How to use a PID (proportional, integration, differentiation) circuit? Is there any pictures showing how it is connected and what is its use? thanks~
  19. zgnoh

    Need help on a project changing the strength of water of shower.

  20. zgnoh

    Need help on a project changing the strength of water of shower.

Top