Hi, I'm doing a small little experiment and have designed a up/down counter on a wish board using 2 7483 adder ic, a shift register and a 555 monostable one-shot timer. I use one of the 7483 ic as a subtractor by making the B inputs to decimal 15 so that it will do a reverse adder while another 7483 ic as a adder by making the B inputs to decimal 1. The output of my adder is connected to the input of the 74194 shift register while the output of the shift register is connected to the inputs A of the subtractor (The shift register is connected to parallel mode). The problem now is that in order to create a up and down, I need to change the B inputs for adder to a decimal 0 or 1, and B inputs of subtractor to decimal 0 or 15 everytime by moving the wire to either ground or live in order for the circuit to work. I would like to know if there is any ways for the B inputs to change their decimal value on its own. Should I use an invertor or is there any other ways?

Btw, I'm quite new to all this and thanks for the help in advanced.

 

You can switch a signal from non-inverting to inverting using a 7486 XOR gate.

 

There certainly are other ways to ask. Schematic?

ak

 

There certainly are other ways to ask. Schematic?

ak

 

You can switch a signal from non-inverting to inverting using a 7486 XOR gate.

Thanks much. I found a way to connect 7404 invertor and 7486 XOR gate together using another 555 monostable timer to create signal for both B outputs of the 7483 adder.

 

I'm also trying to make an up-down counter, Found up-counting 'chip' 4511, but to do both needs 2 'chips', 1 to BCD & the 1 to 7-segment. = 1 other why, 4511 counts 0-9, then other circuit only need to count 8-1, so output of 555 & 2 flip-flops can give the 3 bits needed.

 

I'm also trying to make an up-down counter, Found up-counting 'chip' 4511, but to do both needs 2 'chips', 1 to BCD & the 1 to 7-segment. = 1 other why, 4511 counts 0-9, then other circuit only need to count 8-1, so output of 555 & 2 flip-flops can give the 3 bits needed.

CD4511 isn't a counter, it's a BCD to seven segment decoder.

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