I've made a few circuits with 74 series TTL, counters, BCD and 7 segment drivers, things like that. They've worked out well. I've just spent a few hours making a similar circuit with CMOS chips, and things aren't going well at all.
I found that the output of my CD4511BC BCD-to-7 Segment Latch/Decoder/Driver output Vdd to the 7 segment when it was supposed to, but during those moments when it was supposed to output 0 to an LED, the voltage dropped only about a volt.
So I looked at the datasheet and found a typical applications page. It shows a schematic of the chip used with a common anode LED, with a transistor in between!
TL;DR --- with CMOS I have to use transistors on the output to drive a 7 segment? In TTL I just did it directly.
Thank you
I found that the output of my CD4511BC BCD-to-7 Segment Latch/Decoder/Driver output Vdd to the 7 segment when it was supposed to, but during those moments when it was supposed to output 0 to an LED, the voltage dropped only about a volt.
So I looked at the datasheet and found a typical applications page. It shows a schematic of the chip used with a common anode LED, with a transistor in between!
TL;DR --- with CMOS I have to use transistors on the output to drive a 7 segment? In TTL I just did it directly.
Thank you