11

PS2601

Ω

1

0.1

0.01

100

1000

As mentioned above, noise induced by the fluctuation of supply voltage can be removed by proper treatment of the base pin. For

switching of input free from induced noise at normal switching speed, optocouplers with a base pin such as the PS2602 series

are available. If the base pin of an optocoupler is left unused or opened, it typically will pick up external noise. Cutting off the

base pin is also effective in order to prevent it from picking up external noise. See Graph 8-(b).

Figure 2-8. Vo vs. CBE Characteristics