sorry for reposting. I just added some information about voltage rating
of two ICs.
----
according to :

Yes, you can. It's the number 7414 which tells the purpose of the chip.

The C-letter means it is cmos-type (and it needs to be in your circuit,

as you mentioned), and H means it is high-speed-type. It is not
mentioned to be necessary in your circuit, but it is ok to use the
high-speed type, although not necessary.


ps. according to the datasheet, 74HC14N is Hex Inverting Schmitt
Trigger and 74C14 is Hex Schmitt Trigger.


Both ones are inverting. There are mistake, or maybe the maker of the
datasheet of the 74C14 has considered the "invertingness" a "special
feature" which wouldn't be necessary to tell on the header.

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From: Gerard Bok - view profile
Date: Tues, Mar 28 2006 5:16 am
Email: (Gerard Bok)
Groups: sci.electronics.repair
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On 28 Mar 2006 02:02:51 -0800,
wrote:


Yes, you can. It's the number 7414 which tells the purpose of the chip.
The C-letter means it is cmos-type (and it needs to be in your circuit,
as you mentioned), and H means it is high-speed-type. It is not
mentioned to be necessary in your circuit, but it is ok to use the
high-speed type, although not necessary.


While you are right with the 'general picture' that it is the
function that counts, you may well be wrong here :-)

Use in a C-meter, as the poster mentioned, is likely to be
dependant on the Schmitt trigger's threshold.
And that is one of specs that varies between different
technologies :-)


--
Kind regards,
Gerard Bok




thanks to replies. According to the datasheet the VCC of of C is higher

than HC part. In the capacitance meter i am planning to make, its
supply voltage is 12 volts but 74hc14n VCC pin max is 6 volts only.
That might be the problem. With the transistor tester using also 74c14,

its supply voltage is 6 volts. In this case, the 74hc14n might be
suited as substitute but not in the capacitance meter with the supply
voltage of 12 volts. (Because 74c14 has a Vcc ranging from 3.5-15 v but

74hc14n only up to 6 volts). Am I right?

tnx again,


ian