Electronic Circuits for the Evil Genius 2/E

SECTION 4Two Projects and Then Some More

ENOUGH OF THIS PLAYING around. Let’s do something.

Lesson 12 Your First Project: The Automatic Night Light

We combine our knowledge and the components to make an automatic night light. It dims in the light and brightens in the dark. Using the LDR, build the circuit shown in Figure L12-1 on your breadboard. The photograph of the circuit appears in Figure L12-2 (see also the Parts Bin).

Figure L12-1

Figure L12-2

PARTS BIN

D1—1N400X diode

P1—100 kΩ pot

R1—22 kΩ

R2—470 Ω

LDR—1 MΩ dark

Q1—NPN ...