hi, this is my first post,
i'm from portugal and i can speak english a bit, i don't have many knowledge of electronics and i came here because i believe someone can help me..
i'll try to explain what i want to do..
i want to control a light (it can be a led), using a pushbutton like this for example..
**broken link removed**
and i don't have any idea how to use this. i want that when i click the button the light turns on, and when i click again it turns off..
i want this kind of button and not an switch because i want that the light turns off when i cut the power, and when i turn the power on the light doesn't turn on until i click the button.
please apologise for my bad english, but i hope someone can understand and help me.
You should really connect the unused inputs (pins 9 - 13) of the CD4027 to either ground or +ve. CMOS inputs that are floating can cause the IC to take a lot of current.
There are 21 LEDs. There is nothing to limit the current and we don't know if some of the LEDs are in series.
If the LEDs are all in parallel and use 20mA each then you need a darlington transistor that can switch 0.42A from a low current from the CD4027, not a little BC548 transistor.