SN7414 Application circuit For Conductivity Sensor

Rahul Surawase11

Other Parts Discussed in Thread: SN7414, SN74HC14, SN74LVC1GX04, CD4060B

We need Application design circuit for SN7414 Sch-mitt trigger IC, We use this ic for read the conductivity sensor output but its not work properly its gives some fault triggering plus which affect on my applications

over 6 years ago

0 Emrys Maier over 6 years ago

TI__Guru* 96591 points

Hi Rahul,
Can you share the circuit that is causing problems?

0 Rahul Surawase11 over 6 years ago in reply to Emrys Maier

Prodigy 30 points

0 Emrys Maier over 6 years ago in reply to Rahul Surawase11

TI__Guru* 96591 points

Just out of curiosity, is there a specific reason why you are using the very old BJT logic rather than a newer device like SN74HC14?

Can you explain what this is supposed to do? It looks like some sort of oscillator, but I'm not familiar with it... and since there are connections going off page, I'm even more in the dark.

Also, can you describe what it is doing that is incorrect?

0 Rahul Surawase11 over 6 years ago in reply to Emrys Maier

Prodigy 30 points

Hey, Thank you for the reply.. We are using this circuit as a means to generate a frequency based on the conductivity sensor situated between Pins 1 and 5 of SN7414(Please refer the Dig. provided before). the output is taken from pin 4 which goes to the capture pin of our microcontroller. The problem we are facing is that even when the Sensor is kept floating, we are getting random frequencies at pin 4. And also, Even when the Conductivity sensor is kept in a stable Solution, we are getting fluctuating frequencies at the output. Therefore we would appreciate a component wise explanation for our application circuit and for a better understanding , a application design circuit for generating a 50Khz Frequency.

0 Emrys Maier over 6 years ago in reply to Rahul Surawase11

TI__Guru* 96591 points

I'm certainly no expert on how your system works, but I will give you my opinion.

I would recommend using a different approach. If you need a 50 kHz clock that is very consistent, a crystal oscillator with the SN74LVC1GX04 crystal oscillator driver would be the best approach.

Here's an application report that talks about the process for the design of this type of oscillator: www.tij.co.jp/.../szza043.pdf

You could also make a less accurate but more cost effective oscillator with CD4060B. It will allow you to make a higher frequency oscillator then divide it down to 50kHz with the built-in counter.

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SN7414 Application circuit For Conductivity Sensor