Timeline for BCD to 7 Segment is producing too little voltage
Current License: CC BY-SA 3.0
9 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Mar 18, 2016 at 21:53 | comment | added | user103993 | As for the kind of display that the chip can drive you have to look into the datasheets, sometimes it can be a bit hidden but it will usually mention it somewhere. If you look on page 3 of the datasheet it mentions it's used for common anode displays directly. Some datasheets are even nice enough to include example images of circuits, if you look at the datasheet for the MC14511 you'll see it shows you a variety of ways you can use the chip on page 6. MC14511 Datasheet | |
| Mar 18, 2016 at 21:42 | vote | accept | Ryan | ||
| Mar 18, 2016 at 21:42 | comment | added | user103993 | If you're looking for a direct chip replacement as opposed to replacing the 7 segment display then try the MC14511, you might need to use different resistors on the outputs of the chip but it will do what you're after | |
| Mar 18, 2016 at 21:41 | comment | added | Ryan | Right now, this circuit is just a prototype to make sure I understand the components (and to identify problems like these), so changing the circuit doesn't really matter too much to me right now. The reason I like my current displays is because I've already created prototypes assuming their exact dimensions (as I'm doing something a bit odd with these where their physical dimensions are very important. | |
| Mar 18, 2016 at 21:41 | comment | added | Ryan | Thanks again. Instead of buying a new display, could I just buy a different chip? Also, would you mind giving me a hint on how to identify if the chip operates a cathode or anode display? When I look at the datasheet for the SN74LS47N, I can't find where it describes what kind of display it operates (anode or cathode). I'm sure I'm missing something obvious, I just don't want to make the same mistake twice. | |
| Mar 18, 2016 at 21:37 | comment | added | user103993 | You can use pull up resistors on the outputs, but that's an extra resistor you have to add to each output and depending on the size of the pullup resistor will limit too much current and make your 7 segment display dull. If you do buy a new chip don't go for the SN74LS48 as although it has a high output it can only source around 2mA and you won't be able to use it to drive your 7 segment display directly. Personally I'd buy a common anode 7 segment display, that way you don't need to change your current circuit | |
| Mar 18, 2016 at 21:33 | history | edited | user103993 | CC BY-SA 3.0 |
added 1135 characters in body
|
| Mar 18, 2016 at 21:26 | comment | added | Ryan | Thanks, that really helps. I have a common cathode display. Does this mean this chip won't work? Right now, the output is inverted (as in for every number the parts that should be lit aren't, and the parts that shouldn't are). Edit: Looking at other responses, it does. Oh well. Time for new chips. | |
| Mar 18, 2016 at 21:24 | history | answered | user103993 | CC BY-SA 3.0 |