Page 26 - Electronics Starter Kit_EN

The first condition:
0. 7 ≤ in the dark

≤ ( + )
·

If we considered = 0. 7 and LDR = 600KΩ

( 600 Ω + )
600 Ω
0. 7 ≤ 5 · , ≤ 3. 685 Ω

The second condition:

0. 7 > in the dark

> ( + )
·

If we considered = 0. 7 and LDR = 6KΩ

( 6 Ω + )
6 Ω
0. 7 > 5 · , > 36. 857 Ω

So 3. 685 Ω ≥ > 36. 857 Ω , but 3.685MΩ will not work, because it won’t give

enough current on the base to make the LED light up.

The third condition:
− 0.7 5 − 0.7
< , < , < 215 Ω
20µ 20µ

So 215 Ω > > 36. 857 Ω , thus, any value between 215KΩ and 36.857KΩ will

work.

4.6 Example Picture

25

Electronics Starter Kit r.00 www.plusivo.com