# need help for circuit guidance (123d.circuits)

i am using https://123d.circuits.io/ simulator.
i want to know if what i desgined will work in real life.
i desgined a scoreboard 0-99 that you can increase decrease and reset by push a button.

this is my design:

*you need to change the voltage to 12v

the upper 14 resistors are 10K ohm
the other 14 resistors are 330 ohm
the buttons resistors are 1K ohm

1. do i need to change/add/remove something in the hardware?
2. what is the brigtness? in ma

You need to post a circuit diagram, not a ratsnest wiring diagram - cannot follow that.

You need to post a circuit diagram, not a ratsnest wiring diagram - cannot follow that.

You said more tactfully than I could have. There are no words (polite ones anyway) to describe that mess...

and based on what you supplied so far...

Consider swapping 10K with 1K

So all of your transistors have 1K at the base and all your buttons use 10K... opposite to what you have said.

haha you killed me...sorry
R2=10K ohm

pwillard:
and based on what you supplied so far...

Consider swapping 10K with 1K

So all of your transistors have 1K at the base and all your buttons use 10K... opposite to what you have said.

why?

Do you want your transistors to reliably switch or not? How did you come up with 10K?

WHY? Without going deep into concepts like transistor minimum gain, saturation and reading a datasheet (eek)... know this. A transistor (not a mosfet) base pin needs only a very small voltage to work, but to switch full on it needs a certain amount of current. A 10K resistor limits current from the arduino pin to a point that is so close to where the 2N2222 comes out of it's full-on switching state ( That's called saturation and is is a point where no additional base current will make the transistor switch any more "on" ) that your results may be unpredictable since your transistor may not actually be fully ON. This is not what a switch circuit is aiming for.

FYI:
Using a 1K value base resistor with a 2N2222 and 5 volt digital logic for switching circuits goes back to qualified engineers in the late 1960's right up until today. (You see physics doesn't change much) Do you really want to doubt the wisdom of 50 years of engineering?