hi everyone,

i am assembling a capacitance tester using ic 74c14 schmit trigger. The
available IC in my box is 74HC14N. The question is, can I use 74HC14N
as a substitute instead of 74c14?

thanks in advance,
ian

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

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.

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

In article ,
says...
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 :-)


Also, the C part can run from a higher VCC that the HC part. That might
pose a problem if the VCC is 9V or so.

Jim

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

In article .com,
says...
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

Yes, you are right and I would not run an HC part at 6V. I never like
to take a part right to the edge of the envelope. I'm sure they spec'ed
in C parts for the VCC range and the trigger threshold value.

Jim