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Test 发表于 2021-4-4 16:24

Testing 74LS05N (open collector)

I'm trying to testing an hex inverter 74LS05N (open collector) but the software gave me test failed... I tried with about 10 pieces and doesn't seems work.. Only 74HC05 (OD) is open drain??!? seems working. Please help me

admin 发表于 2021-4-6 15:40

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OD=OC

Test 发表于 2021-4-6 22:10

Ah ok, so why call them OD and not OC? What's OD means?

Test 发表于 2021-4-6 22:24

7405 or 74LS05 = TTL technology => the circuits is called Open Collector
74HC05 => CMOS technology => different circuits to achieve the same behaviour as Open Collector, but the circuit is called
Open Drain

In the list you treated the 7405 as if it was a REGULAR inverter, not an OC/OD one
Also i checked the 7404, and have the same pattern of 7405, and this is wrong.

And the 7405 should be renamed 7405 (OC)

Test 发表于 2021-4-6 22:31

7404 = classic hex inverter 7405 = classic hex inverter with Open Collector (OC)

The 74HC05 (OD) is ok because the 74HC05 is the classic hex invert (in CMOS technology) with Open Drain (OD)

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