Yes VCC on 5 and ground on 12 does seem a bit odd.
I am in the UK but I need two of them.
I'm toying with the idea of getting two from Cricklewood Electronics or
using 4028's and MPSA42's which seems like a better idea but it means
finding space for 20 transistors on the board.
On Thursday, 28
I think I'd agree.
I've used the Russian K155ID1 drivers from eBay which seem to work OK
(after finding out the first Eagle library I used had the power supply pins
swapped so VCC was on pin 12 - reminded me to check new library symbols
every time now) but it's clearly been a long time, since
That didn't work either, I think I've been sold a duff one.
Craig
On Wednesday, 27 September 2023 at 14:30:22 UTC+1 Craig Garnett wrote:
> Thanks Nick, I'll try that.
> Back in my day I mostly used 4000 CMOS, I didn't do much with TTL.
>
> On Wednesday, 27 September 2023 at 11:23:17 UTC+1 Nick
Thanks Nick, I'll try that.
Back in my day I mostly used 4000 CMOS, I didn't do much with TTL.
On Wednesday, 27 September 2023 at 11:23:17 UTC+1 Nick Sargeant wrote:
> I'd agree with the above. To make sure you are avoiding any indeterminate
> states, pull all of the inputs up to +5v with a
I'd agree with the above. To make sure you are avoiding any indeterminate
states, pull all of the inputs up to +5v with a resistor of about 2k2 to
4k7. Then, for the inputs you want low, jumper those inputs to ground. The
pull-up resistors will mean you get a good solid '1' without the jumper,
I tried those suggestions and nothing changed, there's around 4ma total
through the LEDs now so it shouldn't be in meltdown mode.
On Tuesday, 26 September 2023 at 17:45:06 UTC+1 Craig Garnett wrote:
> Thanks,
> I'll give those suggestions a go.
>
> On Tuesday, 26 September 2023 at 16:05:17
Thanks,
I'll give those suggestions a go.
On Tuesday, 26 September 2023 at 16:05:17 UTC+1 gregebert wrote:
> 74xx TTL devices have a rather high input-low current, on the order of
> 1mA, so you should use a much smaller pulldown resistor, say 100 ohms, or
> perhaps none at all. Logically, it
74xx TTL devices have a rather high input-low current, on the order of 1mA,
so you should use a much smaller pulldown resistor, say 100 ohms, or
perhaps none at all. Logically, it should not be possible for more than 1
output to get driven low on the 7441, but that only applies if all
