Hi, I bought the CMOS chips (NAND, NOR etc.), but it does not fit to the breadboard. The problem is that all chips have too wide gap between its pins. How can avoid these problems for my next shopping?

 

Get a breadboard that has its holes drilled on a 0.1" by 0.1" grid.

hgmjr

 

I got it, but some chips fit and the other don't.

 

Logic chips have been made in the dual-inline-plastic (DIP) package for nearly 50 years.
the pins are exactly 0.1" apart and the rows are exactly 0.3" apart. The pins are on an angle to hold the IC on a pcb before soldering. Bend them straight.

 

Just a "follow-on" to Audioguru's post,

Be careful when "straightening" the pins; not hard to snap them off unless you're careful.

You used to be able to buy "IC Insertion Tools" - these nifty devices had a U-shaped channel that caused the IC's pins to be centered at 0.3" apart, with a button to push at the top to help you insert the IC into the PCB. These are hard to find nowadays. You can more or less make do if you can find a pair of 90° angle needle nose pliers; or you could make your own IC insertion tool from some inexpensive aluminum angle and some spacers.

Sounds like a good project to build and document.

 

IC insertion tools are still available. They run two bucks for the plastic ones, up to $20 for the better ones.