Hello all,
I've been working on a circuit on Circuit Wizard for my electrical engineering class. It's supposed to count up to 10 using a clock and a 7 Stage Binary Ripple Counter (IC 4024B) and display the BCD on a 7-Segment Display using a 7-Segment Decoder and Driver (IC 74LS47).
The circuit looks like this: http://dl.dropbox.com/u/5764194/CountingCircuit.PNG
Running in logic view: http://dl.dropbox.com/u/5764194/CountingCircuitLogic.PNG
It works but doesnt display the BCD on the 7-Segment Display for some reason
Can anyone help
Thanks,
Callum
I've been working on a circuit on Circuit Wizard for my electrical engineering class. It's supposed to count up to 10 using a clock and a 7 Stage Binary Ripple Counter (IC 4024B) and display the BCD on a 7-Segment Display using a 7-Segment Decoder and Driver (IC 74LS47).
The circuit looks like this: http://dl.dropbox.com/u/5764194/CountingCircuit.PNG
Running in logic view: http://dl.dropbox.com/u/5764194/CountingCircuitLogic.PNG
It works but doesnt display the BCD on the 7-Segment Display for some reason
Can anyone help
Thanks,
Callum
-
The LS47 has a maximum supply voltage of 7; you're giving it 9v - at least, I assume so: you don't show power supply connections to the ICs.
The selected output of the decoder is low (for example, with BCD 0 in, only segment g is high.) That means that the display must be connected to the positive supply- your circuit shows it connected to the negative supply.
"It works but doesnt display the BCD on the 7-Segment Display for some reason"
What *does* work? The outputs of the counter, for example?
Edit: If the decoder outputs change in the way you expect, and yet the display doesn't work, then perhaps the display is the wrong sort- the decoder needs a common anode display, with the common anode taken to the positive supply. That way, a decoder output which is pulled low illuminates a display segment.
The selected output of the decoder is low (for example, with BCD 0 in, only segment g is high.) That means that the display must be connected to the positive supply- your circuit shows it connected to the negative supply.
"It works but doesnt display the BCD on the 7-Segment Display for some reason"
What *does* work? The outputs of the counter, for example?
Edit: If the decoder outputs change in the way you expect, and yet the display doesn't work, then perhaps the display is the wrong sort- the decoder needs a common anode display, with the common anode taken to the positive supply. That way, a decoder output which is pulled low illuminates a display segment.