Hello I have to hand in my GCSE electronics project tomorrow and my teacher is awful and knows nothing about about electronics. ANyway my problem is that I have a 4026B chip with a seven segment display. I have connected it up and all the segments light but it wont go above 0. The chip does not seem to take an imput,
I put an input in pin one but it stays on 0. Any swift help would be greatly appreciated and may save me from failing

 

Have you got the datasheet for the device?

If not then.....

http://www.megatronics.lk/data/4000/hcf4026.pdf

Read pages 1 and 2 then you should know the answer.

If you still have problems then if you have time, post the schematic, if not then list the 4026 pins and what they are connected to.

 

Hi, yeah I do have the pin out,

Pin 1 - Input
Pin 2- 0V
Pin 3- +9V
Pin 4 - Nothing
Pin 5 - OUT
Pin 6 -Out put f
7 - Output g
8 - 0V
9 - Output d
10 - Output a
11- Output e
12 - Output d
13 output - c
14 - Nothing
15 - Reset
16 - +9V

 

What is Reset - pin 15 - connected to?

What is Clock - pin 1 - connected to?

 

Reset goes to 0V through a 47k resistor and up to 9v through a switch. PIN 1 goes to a deboucing circuit although at the moment i putting any pulse into it. I should accept aby pusle and change number, even current from your hand should make it move but it just stays on 0

 

Short out the 47K resistor and try it.

 

Make sure that the Clock Inhibit pin is tied lo, clocking pin1 with a +ve edge should advance the counter, pulling the Reset pin high will clear all counts, so make sure the switch connected to the Reset pin is open with the pin grounded with your 47k resistor.......finally good luck 8)

 

I dont think that is exactly right. Pin 9 and pin 12 can't be "output d" unless the chip is screwed up. Either pin 9 or pin 12 is "output b" I recommend that you have 360 ohm resistors between the pins of the display and the output pins. The display might not be as bright, but it will a) reduce the chances of the LED's burning out, and b) work with the rest of the circuit.

 

mstechca

I took pin 12 as output d to be a typo as this shows...
The reason I put a link to the datasheet is to make sure that the student has it AND reads it.

The 4026 is not recommended for directly driving led displays. The recommended method, one transistor per output via base resistor, is shown in the datasheet. If the datasheet is read then the student has enough information to get the circuit working within manufacturers specifications.

Asking for help the night before a project has to be handed in, irrespective of how far the project has been developed, is too late.

 

lol@ Pilot..........You sound just like his teacher hehehehehe.......

Help, hope you got full marks after all the assistance offered here :lol:

 

Thanks Chippie. :lol: :lol:

I remember what I was like as a student so I can only pity the good tutors.

That last comment is no reflection on the author of this topic and I hope they sorted out what was needed.

Oh the fun of making a bit of money building wah wah & fuzz circuits for the local guitar freaks instead of concentrating on what I should have been doing.