i need help extending the keys finder project. can someone help me out????

[logan_dslasher]

i must have totally logged out.. maybe it remembered my login info.. i'm sorry..

anyway, i think i'll just stick with the elctret mic i have.. my adviser just called.. he wants me to come over his house.. we're going to work on the project.. i have to go.. i'll let you know what we can accomplish..

bye..

 

[audioguru2]

Don't forget your discovery that the CD4049 is a lousy linear amplifier and that a CD4069 would be better, would operate with less current  has fewer number of pins so is smaller.
Good luck.

 

[logan_dslasher]

hi! this day was not like what i imagined it to be.. when my adviser and i met this afternoon, he asked if i had everything with me. i said yes. he asked for the circuit. i handed it to him. he also asked for the spare components i have, including the bread board.. i also gave him the printouts i have - those that were from this forum and also the msn conversations.. after that, he walked away..  he's going to work on the circuit by himself. he said he will just give it to me at school on MOnday... i never got the chance to try the things that you have advised me...

anyway, i guess it's better this way.. at least  he won't totallt blame me if this thing doesn't really work.. maybe, i'll just tell you how his work on the circuit went when i see him on MOnday..

How will i learn if i can't see how my project is done? 

 

[logan_dslasher]

good day! has anybody built the whistle responder circuit and made it work? my adviser thinks it'll never work.. he said that the IC used (CD4069 CMOS Hex Inverter) can never be used as an amplifier..

i want to know if anybody had already made the circuit with a 4069 IC..even if you haven't built it, i need your opinion if a 4069 can be used as an amplifier like that in the whistle responder circuit..

thanks again..

 

[logan_dslasher]

good day! has anybody built the whistle responder circuit and made it work? my adviser thinks it'll never work.. he said that the IC used (CD4069 CMOS Hex Inverter) can never be used as an amplifier..

i want to know if anybody had already made the circuit with a 4069 IC..even if you haven't built it, i need your opinion if a 4069 can be used as an amplifier like that in the whistle responder circuit..

thanks again..

correction.. i mean a CD4049.. i got confused.. sorry...

 

[Staigen1]

Hi Logan

Your adviser is totally wrong, it can be used as an amplifier, and a good amp too!
You almost had it working when your adviser took it apart from you, he should be ashamed!

//Staigen

 

[logan_dslasher]

hey! i need proof! can you please give me alink to a site or something that says all about this CD4049.. all i'm getting out of google are PDFs.. they usually contain basic infos..

 

[Staigen1]

Hi

There is an aplication note fron RCA about this, i will check later for the name of it!

//Staigen

 

[audioguru2]

Hi logan,
I have used the CD4069 as a linear amplifier many times and it works well. RCA had an appl. note which is also in National's AN-88 applications note about their 74C04, which is the same as the CD4069.

The CD4069 is completely symmetrical, so operates very well as a linear amplifier and has a fairly low current so has symmetry with high gain.

The CD4049 is fairly high current and is terribly assymmetrical. I haven't seen one. Since it is high current then I think its gain will be low.

View attachment 38450

View attachment 38451

 

[logan_dslasher]

A 4069 is better than a 4049, right? i will try a 4069.. have to go now.. i have a class.. i will re-design the circuit while attending my class. i'll have it sent to you for checking..

thanks..

 

[audioguru2]

My 1st graph shows that a CD4069 or 74C04 inverter with a 3V supply and a high resistance as a negative feedback resistor and a low resistance as its inverting input resistor has a voltage gain of about 500 at low frequencies. The Whistle Responder mic preamp can't have a low value for its input resistor so its gain will be a little less than 500.
Our Keys Finder Project uses CD4069 inverters as linear amps.

 

[logan_dslasher]

hi!

i skipped class to ask you guys about something.. my adviser wired the circuit in the breadboard.. he said that although he wired it correctly and have the same output voltage, the circuit is still not functioning.. he concluded that the circuit will not function.. he said that i should replace the linear amplifiers.. IC1a, IC1b, and IC1c.. he wants me to replace it with transistors or OPamps.. i don't know how? is that possible? how am i suppose to wire them?

i still  think it would be better to use a 4069 instead.. but i am not sure if i will make the correct design with a 4069.. it has only 14 pins compared with 16 on the 4049.. besides, it has a different pin configuration..

 

[logan_dslasher]

audioguru sent me this once..View attachment 38452

 

[logan_dslasher]

so the pin equivalent is:


  4049                            4069
pin 3                  =            pin1
pin 5                  =            pin3
pin 7                  =            pin5

so on...
are my assumptions correct?

 

[logan_dslasher]

Everybody's sleeping!! 

can you please confirm my assumptions as soon as you are available? thanks a lot.. i'll wait.. 

 

[Staigen1]

Hi Logan

I found the appnote on my computer in the end, it was not in the book! ;D
I found two versions of it!
Here they are:

//Staigen

AN-88.pdf

AN-0088.pdf

 

[logan_dslasher]

i can't open the AN-88..
can u please re-post it.. tahnks..

 

[audioguru2]

Here is another applications note about the voltage input vs the voltage output of ordinary Cmos logic that is applicable to using inverters as linear amplifiers. The ouput Mosfets are perfectly symmetrical:

AN-90.pdf

 

[audioguru2]

so the pin equivalent is:

 

[logan_dslasher]

what can you say about my professor's idea that i replace the inverters with transistors and opamps? i read them tomorrow.. i have to go now.. tahnks..