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Other contacts on the breadboard are linked vertically in rows of five; the five

points are connected electrically by metal strips. Most folks place chips in

the middle of the circuit, straddling the little aisle with each pin of the IC in a

contact hole. That way, each pin of the IC is electrically connected to four

other contacts, making it easy to connect other components to IC pins.

Don’t fry your board! These things are very susceptible to heat. Shorted com-

ponents can melt them. Check the components with power on to make sure

that nothing overheats. Also, they are designed only for low-voltage DC pro-

jects, so don’t apply too much juice.

Figuring and finessing the layout .......................................................

How you arrange items on a breadboard won’t look exactly like how you’ve

arranged items in a schematic. You have to pay attention to a few issues

when laying out components on your breadboard. The schematic shows the

elements of a circuit and connections, but a breadboard is arranged to make

the most efficient connections possible using the holes and connectors avail-

able. Here are some tips to keep in mind.

Pin numbering:ICs have pins that are numbered counterclockwise, starting

at a little notch or dot indicator (see Figure 4-8). You should place all ICs point-

ing in the same direction. This helps you avoid inserting an IC backwards and

also helps you keep track of the pin numbers. Use various pins, as specified

on the IC datasheet, to connect to +V, ground, and other components.

1 2 3 4 5 6

7 8

9

14

13

12

11

10

Clocking mark

Pin numbers Pin numbers

Figure 4-8:
The IC pin
numbering
schematic.

Chapter 4: Running Down the Skills You Need 67