All Questions
65
questions
8
votes
3
answers
8k
views
Connecting unused logic gates
Logic gates like AND, OR, NOT etc. often come packed as arrays in ICs.
Sometimes not all gates are used in a project. I would like to know how the remaining unused gates should be connected to ...
- 575
2
votes
1
answer
2k
views
Combining CMOS and TTL logic
I have a bunch of 74LS383 (TTL octal transparent latch with three-state outputs) and MM74C83N (CMOS 4-bit binary full adder) that I would like to connect together. I need to connect the output of the ...
user17592
3
votes
1
answer
251
views
Is there relation between logic chip names and their internal structure
I know that for instance an ATMega328 is a 8 bit MCU with 32k of program space, the same can be said for most other MCUs and some other ICs with a direct relation between the name and internal specs. ...
- 492
2
votes
4
answers
1k
views
Do logic families use different type of transistors?
Do the logic families such as TTL and CMOS represent only different logical structure? Or do they also use different type of transistors? Latest microprocessor chips with millions of components use ...
- 12.2k
1
vote
2
answers
203
views
More advice desired on my Model Railroad Building light controller circuit
Building is built in O Scale (1/48) and has 40 rooms that are lighted independently (masked out from each other with walls) Rooms are lighted with White LEDs. The rooms will light one at a time (but ...
- 15
11
votes
4
answers
4k
views
Should I use CMOS vs. TTL?
Now, I know that this question has been asked so many times that it seems like I'm trolling, but I must point out that I couldn't find the right answer to this question anywhere.
So yeah, CMOS and ...
- 1,947
0
votes
3
answers
1k
views
Synchronous 4-Bit Up/Down Counters preset
I have a synchronous 4-bit up/down counter, and in the data sheet it stands that there are 4 pins where I can enter a 4 bit preset number, but it doesn't say what this number represents. I believe ...
1
vote
2
answers
636
views
Can Arduino power and hookup to logic chips?
I am making a device that has two external interactions i.e. a button and a infrared sensor. My only problem is that I am using a logic chip for this because it would save me time coding on the ...
- 348
1
vote
2
answers
2k
views
How do I connect a 555 timer to a CMOS Input?
I designed the following circuit, using a 555 timer, to supply a single trigger pulse with the same width to digital circuits, no matter how long the button is pressed. The actual pulse output works ...
- 199
1
vote
1
answer
476
views
Honeywell Dead Reckoning Module GPS Problems
This was previously posted in the Stack Exchange forum and I was referred here.
I'm currently trying to connect a Honeywell DRM4000L to a GPS module. The DRM is a dead-reckoning device which takes a ...
- 13
1
vote
1
answer
236
views
Communicate with unpowered CMOS
I'm using some CMOS chips (4021 shift bit register, CD74HCT164E serial in parrallel out, 4066 quad billateral switch, etc...)
I'll have some parts of the circuit on or off, but to economize maximum ...
- 1,818
-4
votes
1
answer
2k
views
How to know if an IC is made up of TTL or CMOS?
Here I look at the data sheet. There is no indication about the transistors:https://www.fairchildsemi.com/ds/LM/LM324.pdf
- 12.2k
5
votes
3
answers
4k
views
Which logic gate family is used in a PC? TTL or CMOS?
I read that the propagation delay of CMOS logic gate is longer than TTL; therefore they are not used where speed of processing is important. I thought computers or computer cpu is using CMOS. ...
- 12.2k
8
votes
2
answers
2k
views
What should be considered when sizing trace widths for digital logic signals?
For traces that carry a static DC current, it's pretty easy to calculate the minimum trace width based on the required ampacity of the trace. However, I'm not sure what should be considered when ...
- 1,753
5
votes
3
answers
2k
views
Driving LEDs / other small loads with a 74HC06 or similar inverter
I was recently reverse-engineering some firmware (and other bits) from a router, and spotted that the front panel LEDs were driven from a 74HC06 hex inverter gate chip rather than a proper LED driver.
...
- 10.8k