![]() | ![]() | ![]() |
| |||||||
| General Electronics Chat This forum is for general chat about electronics, eg: Dont know what a part does? Dont know how to read a circuit? Want to get an opinion? |
![]() |
| | Tools |
| | #1 |
|
Hi all, I have a comparator LM339M, what is its main purpose ? It has 4 inputs and 4 outputs as well as a Vcc and ground connection. When do the outputs go high ? Can you explain the basics. I do'nt have a specific purpose intended for it, I just want to know when outputs 1-4 go high or low and when and why..... Thanks in advance.... Jim
__________________ "Yesterday is History, Tomorrow's a Mystery" | |
| |
| | #2 | |
| Quote:
__________________ Creationists have a world of evidence | ||
| |
| | #3 |
|
Here is a great site that will help you to understand most electronic devices, and it's FREE. http://www.datasheetcatalog.com/ The information comes straight from the manufacturers, its faster than posting a question, and you can depend on the acuracy. | |
| |
| | #4 | |
| Quote:
One of the input is called the non-inverting input (+) while the other is an inverting input (-) When the voltage at the + terminal exceeds that at the - terminal, the output is high. When the voltage at the - terninal exceeds that ath the + terminal, the out put is low. Ex: + = 2.5v - = 6v Output =Low... if + =5 - =-6 Output=High... There are also some digital comparators... Where two digital words are compared and the output is either 1 or 0...
__________________ Bharath Bhushan Lohray. M.Sc. Electronics. | ||
| |
| | #5 |
|
I think 339 needs a pull up resistor to output positive. Here's the data sheet ,you should get used to reading them. http://downloads.solarbotics.com/PDF/LM339.pdf You can usually google for a device number and find a data sheet.
__________________ Reality Last edited by cyb0rg777; 8th April 2007 at 07:58 PM. | |
| |
| | #6 |
|
LM339 is a current sinking comparator, so the outputs are either tied to ground, for a logic 1, or high resistance, for a logic 0.
| |
| |
| | #7 |
|
It is basically a saturating op-amp. A little more complicated but that is pretty much what is happening. I always use this site when I come across a part I do not know: http://www.datasheetarchive.com/ | |
| |
|
| Tags |
| comparator |
| Thread Tools | |
| Display Modes | |
| |