d123
Advanced Member level 5
Hi,
The schematic of the discrete SR latch works in the simulator correctly without the diodes from the NOR outputs back to the cross-coupled inputs. On the breadboard, it needs those two diodes from the NOR outputs to function the same as in the simulation, i.e. correctly/as will be needed in the circuit it will be used in.
Expected functionality is:
Power-up = Not Q high (triggered by cd1 to cd4 high blip at power-up)
When cd4 goes high and coincides with timer b going high = Q high
It does this in the simulation without those diodes and on the breadboard only with the diodes.
It makes no sense to me as the diodes are backwards to how I would have expected to need to place them but the sr latch doesn't work a) without those diodes and b) with those diodes the right way round.
Is there any (obvious) reason for this that someone else understands?
I know a discrete sr latch is not an ideal method but beggars can't be choosers, as they say...
Thanks.
The schematic of the discrete SR latch works in the simulator correctly without the diodes from the NOR outputs back to the cross-coupled inputs. On the breadboard, it needs those two diodes from the NOR outputs to function the same as in the simulation, i.e. correctly/as will be needed in the circuit it will be used in.
Expected functionality is:
Power-up = Not Q high (triggered by cd1 to cd4 high blip at power-up)
When cd4 goes high and coincides with timer b going high = Q high
It does this in the simulation without those diodes and on the breadboard only with the diodes.
It makes no sense to me as the diodes are backwards to how I would have expected to need to place them but the sr latch doesn't work a) without those diodes and b) with those diodes the right way round.
Is there any (obvious) reason for this that someone else understands?
I know a discrete sr latch is not an ideal method but beggars can't be choosers, as they say...
Thanks.