untitled

Identifying the + lead on polarized capacitors and LEDs is easy because the +

lead is longer than the ground lead. For transistors and integrated circuits

(ICs), you have to take a look at the datasheet to find out which pin to connect

to +V and which pin to connect to ground. A datasheetis the manufacturer’s

specifications for the component. You can read about pins in Chapter 3.

Some components are variable, meaning that they don’t just operate at one

value; instead, you can adjust their values. Variable resistors (also called

potentiometers), variable capacitors, and variable coils are all examples of

adjustable components. You can use these adjustable items to control

volume or tune in a radio station, for example.

Pulling it all together............................................................................

After you understand some of the elements that go into a schematic, we

thought you’d like to have us rundown how to read a simple schematic

sample. The schematic used in Chapter 6 is shown in Figure 4-6. This is a cir-

cuit that includes a microphone and an IC that amplify noises; the circuit

works together with a parabolic(curved) metal dish that helps pick up

sounds.

First, some general rules: A line between two symbols indicates that the two

components are connected by a wire. A connection is also indicated when

a symbol is shown connected by one line to another line with a dot at the

junction.

3

2

6

5

4

IC 1

C 3

C 5

R2 +

+

+

C 4

R3

7

SPEAKER

+

8

1

C 2

R1

+

S1

6V

MIC

C 1

Figure 4-6:

The

schematic

used for the

parabolic

microphone.

64 Part I: Project Prep