Need help with specific automatic dimmer circuit.

Thread Starter

schematicsman

Joined Nov 16, 2007
8
I would like to know and need help from you guys on how to build (wire up ) a automatic dimmer circuit to control multiplexed 5 individual common anode display and or mini bullet type incandescent bulbs ?
 

KeithWalker

Joined Jul 10, 2017
1,299
I would like to know and need help from you guys on how to build (wire up ) a automatic dimmer circuit to control multiplexed 5 individual common anode display and or mini bullet type incandescent bulbs ?
We are not a free electronic design service. Have you tried searching the internet for what you need? What is your electronic experience level? Are you able to design circuits yourself?
If you can find something that may do the job or post a schematic of your attempt to design it, we may be able to offer advice and answer your questions.
Regards,
Keith
 

djsfantasi

Joined Apr 11, 2010
6,962
Just a side note... the “and/or” in your specification will be difficult. Controlling LEDs and incandescent lamps are done very differently. You’ll need different circuits for each type.
 

Thread Starter

schematicsman

Joined Nov 16, 2007
8
Guys I just need a little of your help on how to connect a DC Dimmer circuit that i found on the net to multiplexed 5 digit Common anode?

I have attached a pic of my multiplexed 5 digit common anode circuit _ with it simulated all digits on to show you that it works. and a LDR dimmer circuit i found on the internet I don't know how to connect to my circuit so that it dims the display during the day and lights them up at night so to speak.

[The source DC voltage i will be using will be +5V] //////// And for the incandescent bulbs I was mentioning is also what i am trying find a circuit for as well if later I wanted to connect to .

I hope I am making sense .
 

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Dodgydave

Joined Jun 22, 2012
9,666
You normally put the photo diode/ldr in series with the Anode with a parallel resistor, to dim on darkness and bright on daytime.

You want to dim during the day why?
 

sghioto

Joined Dec 31, 2017
1,556
I hope I am making sense
Did you draw the schematic of the display? It looks completely incorrect. All the anodes of the LED displays are connected to 5 volts. The segments of U1 and U2 are the only ones that show multiplexing. The segments of U3-U5 are hardwired to ground with no current limiting resistors. Then there are 5 PNP transistors (Q1-Q5) that are wired across the 5 volt supply and the emitters are connected to ground. WTH.
 

Thread Starter

schematicsman

Joined Nov 16, 2007
8
Hi, i am a newbie and learning electronics and tried to figured somehow a way to light up 5 digits with the bare minimum parts.
It is just to learn about the device and get the LDR to work both night and day.

Thank you everyone for your help pointing out mistakes.
 
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