Thank you. I will make those changes.Good start, nice to see a clean layout.
Put the 12v - 5v regulator in with the rest of the power supply and label the block"Power Supply", it makes no sense for it to be on its own.
Signals should flow left to right. So your switches should have +5v to left and SWx to right. I'd call that block "Inputs"
Similarly flip your UNO over so SWx comes in from left. There's no need to show the Uno and the ULN2003 disconnected like that unless Signal is going elsewhere.
Put the relay in with the lamps - thats your "Outputs" block. Some would argue that should be on RH side.
On something this simple its not really necessary to break it down, but its good practice for the future.
I am inputting the filtered output from 7812 to 7805. Do I still need them?You need capacitors on input and output of 7805.
How do I calculate the capacitance required? Will 0.1uF work for all?Yes. Capacitors need to be close to IC pins.Don’t forget capacitors on all ICs from Vcc to GND.
I did think about it, but 5V relay would pull more current, so I decided to stick with the 12v ones.Use a 5V relay then you can ditch the 12V regulator, and use a 5V transformer
True, but it will take about the same amount of power.I did think about it, but 5V relay would pull more current,
Thanks. I still haven't decided if I am going to use one or four relay to drive the components.Ditch the ULN2003 and replace it with a 2N7000 (or an NPN with suitable base resistors) unless you are planning expansion where the other drivers will be used.
Thank you. I will make the change.Your switches leave the input pins floating. If the pins have internal pulldowns, the 10K resistors could cause an indeterminate logic level. Common practice is to connect the switch directly from the pin to ground and use an internal or external pullup.
Bob
The voltage after retification may vary from 13 to 22v due to no-load/load characteristics of transformer.True, but it will take about the same amount of power.
Why are you concerned about current?
Do you need 12V for anything else?The voltage after retification may vary from 13 to 22v due to no-load/load characteristics of transformer.
Yes, I could opt for a 9v. Won't the capacitors would become expensive?Do you need 12V for anything else?
Can you not go with a lower voltage transformer?
Not appreciably.Won't the capacitors would become expensive?
Alright, I will compare the costs and make the change.Not appreciably.
You need higher capacitance, but can use a lower voltage rating, which tends to balance out the relative cost.
And you eliminate the 12V regulator, and save some power since you no longer need to drop the 12V to 5V.
100nF ceramic is fine. As said, you need 10uF on outputs of regulators.How do I calculate the capacitance required? Will 0.1uF work for all?
Personally, I don't care for your style of schematic drawing. I think of it as more of a netlist because connectivity is conveyed with a bunch of net names.Beginner. Looking to get advice, suggestions and improvements for my circuit.
Thank you. Does the circuit look fine? Do I need add something to make it more safe and reliable?Personally, I don't care for your style of schematic drawing. I think of it as more of a netlist because connectivity is conveyed with a bunch of net names.
At the very least, you could connect the 5V regulator to the 12V regulator and remove some of the white space.
View attachment 212002
I didn't try to follow the schematic because I don't find that style conducive to understanding circuit intent.Do I need add something to make it more safe and reliable?