Timeline for Why does this two NOT circuit oscillate?
Current License: CC BY-SA 3.0
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| Jun 27, 2017 at 6:21 | comment | added | Jasen Слава Україні |
@Ali Chen unicornelectronics.com/ftp/Data%20Sheets/7400.pdf page 3, (it seems ti has dropped the schematic from its most recent data sheet) there is sufficient pull up there to achieve an unambigous TTL logic high (which is less than 2 volts)
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| Jun 26, 2017 at 14:28 | comment | added | Ale..chenski | @Jasen, no, original TTL did NOT have any pull-ups, please check their actual schematics diagrams, e.g. allaboutcircuits.com/worksheets/ttl-logic-gates/#24 or go straight to Texas Instruments pages. Maybe some modern series do, I am not sure, but it does not change the basic idea. | |
| Jun 26, 2017 at 5:30 | comment | added | Jasen Слава Україні | @AliChen 74xx series TTL has pull-ups on the inputs, not floating. | |
| Jun 26, 2017 at 4:50 | history | edited | Ale..chenski | CC BY-SA 3.0 |
added 479 characters in body
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| Jun 25, 2017 at 21:58 | comment | added | user84299 | Capacitive-resistance coupling is a generic statement, it just sugegsts transfer of energy, doesn't explain what is going on in a specific case. I found an explanation in an article from the 60s. You might be unsure of the details of this circuit, you would have given it if you did. I am sure you know the big picture. The quote you give is a prelude to the transistor multivibrator (TM) which is not in detail how my circuit works. I understand the TM perfectly but the one I gave is more subtle. True there are capacitors and feedbacks but the details differ. This is WHY I posted the question. | |
| Jun 25, 2017 at 0:10 | comment | added | Ale..chenski | @rhody, young man, which part of "...feedback loop by capacitive-resistive coupling network..." did you miss? | |
| Jun 24, 2017 at 21:00 | comment | added | user84299 | Its more complex that you make out. It is true that two inverters in a cycle will have two stable states, 10 and 01. Its only the with the capacitors that makes the state unstable. I'm 90% certain that what we have then is a relaxation oscillator. Thankfully I found a much fuller explanation in an obscure article. | |
| Jun 24, 2017 at 14:51 | history | answered | Ale..chenski | CC BY-SA 3.0 |