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| 74LS14 testing circuit pls |
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| Chriss:
Hmmm... Thanks for this valuable micro schematic. It could be that I killed one of the IC's where I tried the LED with a HI level output. But what is with the other one IC? I didn't connected the LED to the other one IC, just the scope... And on that just scoped IC I have only one gate working. So, the best testing way would be to test it with a LED on a LOW level output setup. |
| Chriss:
Could it be does the IC's was killed from ESD? because they was just stabbed into foam board and put into a PVC small bag when it was delivered to me. |
| PA0PBZ:
--- Quote from: Chriss on April 13, 2018, 06:20:33 pm ---Could it be does the IC's was killed from ESD? --- End quote --- I don't think so, LSTTL is very hard to kill with ESD. Since you never used the other IC with a LED we can forget about killing it that way, so where did you buy them, what did you pay, how do they look and what current do they consume on VCC? I wonder if you got fake ones but I can't imagine why anyone would fake an LS14... |
| TomS_:
--- Quote from: Chriss on April 13, 2018, 05:41:31 pm ---I cant get believe this because the IC's are brand new! --- End quote --- Where did you buy them? I dont think you would blow them by not pulling unused inputs up/down. There must be some other explanation. Personally, in future I would look at AHCT family chips. They have TTL compatible inputs, are super quick (nanoseconds switching time), use very little power because they are CMOS, and can source/sink more current (20mA each way, give or take). Unless its for legacy, I dont think theres much point to using older TTL families any more these days? |
| TomS_:
--- Quote from: PA0PBZ on April 13, 2018, 06:26:12 pm ---so where did you buy them --- End quote --- snap ;D |
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