Powered by Blogger.

Friday 25 July 2014

Control 7404, NOT Gate IC, using Switch

by realfinetime  |  in NOT Gate at  22:26

         NOT gate is commonly used to INVERT a logical HIGH to logical LOW or logical LOW to logical HIGH. Each NOT gate has one input and one output. Commonly used NOT gate IC is 7404. Pinout diagram of 7404 is given below. Each 7404 has 6 NOT gates arranged as shown in the following figure. 14th pin is the Vcc and 7th pin is the Ground.

Recommended operating conditions of 7404

         Recommended operating conditions of 7404 is given in the following table. Supply voltage should be less than 5.25V and greater than 4.75V. A voltage greater than 2V will be considered as HIGH level and voltage less than 0.8V will be considered as LOW level. 

Truth table of NOT gate

          Truth table of NOT gate is given below. NOT gate will give a HIGH output, if the input is LOW. Similarly output will be HIGH, if the input is LOW.
Control 7404 using Switch

          Circuit to control 7404 using switch is given below. 5V is supplied from an Arduino board or from 7805 Voltage regulator. Each 7404 has six NOT gates. Any NOT gate can be used in the circuit. First NOT gate is used in this circuit ( A1,Y1 ).

Explanation of the circuit

          When switch is off, input pin of NOT gate will get connected to ground through the pull down resistor. Gate will consider it as logical LOW, So output will be HIGH and LED will turn ON. If the input pin is left unconnected ( not connected to pull down resistor and switch ), IC will assume itself that, voltage at the gate input is logical HIGH. So, turning off the switch without connecting pull down resistor will not give logical LOW at the input. That is, switch will have no effect in changing the voltage level at the gate input if pull down resistor is not connected. Similarly, when the switch turns on, voltage across the input pin will be 5V. Gate will consider it as logical HIGH. so the output will be logical LOW. This will turn off the LED. A current limiting resistor is provided in series with LED to protect LED from overcurrent. Truth table of this circuit is given below.

Alternate Method

           NOT gate can be controlled by another circuit also. Circuit is done as shown in the following diagram. Here pull down resistor is replaced by a switch. Switch is used to control the connection of gate input to ground. When the switch turns on, gate input get connected to ground. Output is connected to an LED through a current limiting resistor for LED protection. Switch in the previous circuit is replaced by a pull up resistor. Pull up resistor pulls the input pins to HIGH, when switch is closed. If pull up resistor is not used, when switch turns on, power supply get shorted through the switch. This will result in large current and will damage the power supply.

Explanation of the Circuit

              When the switch turns off, gate input pin get HIGH voltage from the voltage source through the pull up resistor. So output will be LOW and LED will turn off. But when the switch turns on, gate input get connected to ground and hence the gate input pin will be at logical LOW. So the output will be HIGH. This will turn on LED. Truth table of this circuit is given in the following table.


  1. I am browsing this website daily and get good facts from here all the time. Aw, this was a really nice post. Kenya evisa processing time, Kenyans can apply for their eVisa in about 15 minutes by filling and submitting the visa application form.

  2. Great article this is really informative and innovative: with new updates.with new updates. It was really valuable. Thanks a lot. Travelers can easily apply for Indian visa online. The Government of India has provided an easy-to-use method to apply for an Indian Visa.

  3. It's good to be back! I thought I've been to this site before, but after reading some of the posts, I realized it's new to me. In any case, I'm glad I found it and will definitely bookmark it and check back often. Is India issuing tourist visas. The Government of India allows foreign tourists to travel to India for tourism. You can apply online for an Indian tourist visa.

  4. I thought I had been to this site before, but when I read some of the posts, I realized it's new to me. Anyhow, I'm glad I found it and I'll be back often. is India issuing tourist visas. Yes, the Government of India allows foreign tourists to travel in India for tourism. You can get an online India tourist visa.

  5. Hii sir, Nice blog. Thanks for sharing. Lots of people query, What is the Indian passport photo size? You can read info about India visa photo requirements via our Indian visa page.

  6. I found so much interesting stuff in your blog, especially its discussion. From the tons of comments on your articles, I guess I am not the only one having all the enjoyment here to keep up the good work. Travelers who want to travel to Turkey. They need a Turkey evisa which is designed for tourism purposes.

  7. Your article is easy to read and understand. I would like to read more articles like this. Getting an evisa Turkey online is a hassle free process. It saves time and money as well.

  8. Knowing where your friends, family, or coworkers are at all times- The ability for friends, family, or coworkers to track travelers wherever they are in the world is a new function of many roaming SIMs that is not simply intended for the mobile phone user. Roaming IoT SIM Card

  9. The concerned website should therefore refrain from establishing links with low-ranking websites with content unrelated to the host website. Including social media share buttons when developing a page is crucial because they aid in good ranking. Philadelphia SEO firm

  10. This is too good article for more information visit here. If you're interested in traveling and looking for some visa company who provide best visa in uk for click here to know more. Turkey Visa

  11. The benefit of using a roaming eSIM card is that you can keep using your same phone number and contacts while travelling. You can also use the same phone plan and data rates as you would at home. Roaming eSIM Card

  12. Thanks for sharing this valuable information with us.

  13. Safety and Risk management software is a critical tool for organizations looking to improve their safety programs and manage their risks more effectively. By implementing this type of software, organizations can improve their safety culture, reduce incidents and accidents, and ensure compliance with regulatory requirements and industry standards.

  14. Thanks for the article, its really very useful.

  15. I'm also glad you mentioned that your company offers affordable leather jackets for women. I'm looking for a good quality jacket that won't break the bank, and I think your company might have just what I'm looking for. Check our collection of leather jackets for men

  16. "This post is a gem! Your ability to make complex topics accessible is truly remarkable. I found myself nodding along with every point you made. Your writing style is engaging and easy to follow. Thank you for sharing such valuable insights. Excited to see what you have in store for us next.

  17. Your offerings are absolutely stellar! I've been a keen observer of your content, and it never fails to inspire. Your articulate presentation and thoughtful analysis make for a captivating experience. Eagerly awaiting more enlightening content from your platform! 🚀📖🎉



All the circuits, published in this blog is only after testing and getting proper results in my private lab. When you try these circuits, you should check the supply voltage, polarity of components, presence of childrens nearby and shorts in the circuits. This website will not be responsible for any harm happened to you or your components caused by your carelessness.

For More Electronic Tips

Blog Archive

Proudly Powered by Blogger.