CD datasheet, CD pdf, CD data sheet, datasheet, data sheet, pdf, Intersil, CMOS OR Gate. CD – Dual 4-In OR Gate. Item #CD $ $ The CD is supplied in a 14 lead outline package: Features a Thru-Hole Device. Data Sheet. Texas Instruments cd Logic Gates are available at Mouser Electronics. Mouser offers inventory, pricing, & datasheets for Texas Instruments cd Logic.
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Imagine that you sit on your PC desk, you pull the keyboard, the mouse is near by, you click the button and the computer boots. Now imagine the same scene, but instead of pushing just a button, you enter the security code! That was one of my imaginations when i was a kid. Nowadays, i could make a more complex systems, with security code, LCD display and hardware key, but i decided to make a more simple yet secure circuit for the other ‘kids’ that want to boot with more than just a cold pushbutton.
There are more simple but less secure circuits. This circuit has a 4-digit security code that is hardware selectable. It can have as many ‘wrong’ digits as you like, but up to 4 ‘correct’ digits.
Also, one digit cannot be more than once in the security code. Suppose for example that you choose to have 10 digit keypad with numbers from 0 to 9. One code could be the numberor thebut the code is wrong! The digit ‘4’ is more than once in the code and that cannot happen. Each ‘correct’ key press will SET a flip-flop. Whenever a ‘wrong’ button is pressed, all 4 flip-flops will be RESET and the code must be entered again from the beginning.
Also, if the code must be entered in the correct order. The keypad can have as many keys as you like.
CD Datasheet pdf – CMOS OR Gate – Intersil
The 4 D inputs are the ‘correct’ buttons. Each one must go to one and only key! For example, someone could connect the D1 to key number 4, the D2 to key number 2, the D3 to key number 9 and Dtasheet to key number 5.
The code to open the lock would be ”. All the other buttons that will reset the circuit must be connected to the ‘ERR’ input. So if the keypad had 10 keys and the code was ” the keys 1,3,4,6,7,8 and 0 must be connected to the ERR input.
The keys can be a push-button with one normal-open contact, connected to the positive VDD of the circuit. Look at the following PCB layout:.
The circuit is designed to operate at any voltage between 5 and 15 volts.
The only thing that needs to be changed is the relay. If you will use normal push-buttons for the keypad, i suggest you use the following circuit instead. This is exactly the same circuit as the previous one, with the only difference on the reset. Instead, it uses diodes connected as OR gates.
It has dattasheet same operation as the previous one, but it is not recommended to be used with a touch keypad! This circuit is significantly simpler and equally secure to the previous one. It needs a smaller PCB an one chip less. The circuit on a breadboard for test. This circuit has the CD Chip included and can be used with touch dahasheet as well. To be more secure, the keypad should be on another remote PCB.
The keypad could be normal pushbuttons. A nice print-out with some kind of artwork and holes that correspond to the keypad PCB-keys, can mask the keypad and make it more elegance. This circuit does not have the chip. It has the same functionality, it is eatasheet, but it cannot be used with touch keypads.
Here is a video from the circuit in operation! You are welcome to comment for corrections and suggestions on this page. But if you have questions please use the forum instead to post it. At 31 May7: At 14 November1: At 28 July7: Cd44072 testing this circuit on breadboard, I found that it would not reset after pressing the correct key-codes. May be an auto-reset feature should be added?
CD4072 PDF Datasheet浏览和下载
I referred some resources and found that it can be done by a timer and some parts. Based on your circuit, I made dataseet version which also include the feature mentioned above and the “disable the keypad when green LED lights” enables again after 5 seconds.
At 3 Octoberdatssheet At 3 September It will xatasheet to spend a lot of time to design and test the PCB. At 2 September Actually one of my Ic’s Pin was broken. But now cd4027 working perfect Anyways thanx for ur time and help Thanx in advance At 25 August I opened a forum thread for you to follow.
Please continue this dstasheet there because it may become a long thread: At 23 August Or the reset line has a problem. Which circuit are you using? The one with the or with the diodes?
At 22 August What should I do??? Plz help me its Ergent: At 1 June0: Is this design able to expand to accommodate a datasheet digit code? At 19 June So, No, it would not work. Suppose now that the code is The R is LOW. When no key is pressed, the S is also LOW from the pull down resistor. From the truth table, R-0 and S-0 makes no change to the outputs.
Now you press the digit 4 first. Look what happens at the truth table in this situation. When you leave the 4th digit, everything returns to LOW. Did i solve your problem? At 19 June9: At 18 June You are talking about the first or the second circuit?
At 21 May You mean you cannot see it clear?
Click on it and it will maximize. Most of the images will maximize on click. Look the video and read the section “The keypad”. It is easy, At 1 March3: At 24 January Thanx At 15 January Then you will connect the RESET daatasheet this new flip flop to the output of the pin 1, that is the reset signal from an error button.
I have not test it but it could work. Test it and post the results. At 15 January How to do it? At 29 December6: I kept it as simple as possible. At 29 December5: U mean,all other button except the 4 code button should be connected to ERR? Simple is nice Kammenos,rather than programming a microcontroller. At 28 December