Title: [UNUSUAL ENTRY] Homemade 7400, better than Logical 7400.
Post by: arupbsk on October 20, 2011, 04:41:32 pm
Post by: arupbsk on October 20, 2011, 04:41:32 pm
At an earlier posthttp://http://dangerousprototypes.com/forum/viewtopic.php?f=62&t=2954 I've said that I didn't have 7400ICs in my drawer.
Surprisingly, the local store was saying 74HC00 out of stock. Hence I decided to make my own 7400 IC.
7400 is a quad two input NAND gate.
Any digital circuit can be made with universal gates like NAND or NOR, even some pretty analog circuits can be made using these as the competition entries show.
To make a NAND gate, I've used the general NAND gate simplified circuit found in some book (I dont remember the name but it might be logic book by m.Morris Mano)
[attachment=4]
I've modified this one with 100Ohm resistor to VCC, and used BC547 transistors.
[attachment=2]
I've printed and etched the PCB successfully for this.
[attachment=3]000_0023[1].JPG[/attachment]
Unfortunately my drillbit broke and I had to give up PCB and made it on a DIP14 IC socket.
Advantages:
Vcc maximum 50V, which is 10x of 7400
Iout max 100mA, which is 5x of 7400
Idle current= 0.00mA, where 7400 takes current and this makes my homemade 7400 more energy efficient.
Disadvantages:
Bot too speedy to work in Mhz timing.
An youtube video with my speech about it (I know there's much background noises).
http://www.youtube.com/watch?v=yJ_jVrxm3lM (http://www.youtube.com/watch?v=yJ_jVrxm3lM)
[attachment=1]101_1339[1].JPG[/attachment][attachment=0]101_1340[1].JPG[/attachment]
Surprisingly, the local store was saying 74HC00 out of stock. Hence I decided to make my own 7400 IC.
7400 is a quad two input NAND gate.
Any digital circuit can be made with universal gates like NAND or NOR, even some pretty analog circuits can be made using these as the competition entries show.
To make a NAND gate, I've used the general NAND gate simplified circuit found in some book (I dont remember the name but it might be logic book by m.Morris Mano)
[attachment=4]
I've modified this one with 100Ohm resistor to VCC, and used BC547 transistors.
[attachment=2]
I've printed and etched the PCB successfully for this.
[attachment=3]000_0023[1].JPG[/attachment]
Unfortunately my drillbit broke and I had to give up PCB and made it on a DIP14 IC socket.
Advantages:
Vcc maximum 50V, which is 10x of 7400
Iout max 100mA, which is 5x of 7400
Idle current= 0.00mA, where 7400 takes current and this makes my homemade 7400 more energy efficient.
Disadvantages:
Bot too speedy to work in Mhz timing.
An youtube video with my speech about it (I know there's much background noises).
http://www.youtube.com/watch?v=yJ_jVrxm3lM (http://www.youtube.com/watch?v=yJ_jVrxm3lM)
[attachment=1]101_1339[1].JPG[/attachment][attachment=0]101_1340[1].JPG[/attachment]