2脚 | 6脚 | 3脚 |
>Vct | >Vct | 低电平 |
>Vct | <Vct | 保持 |
<Vct | 任意 | 高电平 |
555功能表
A.R4/R5的比值大于1 |
B.V3始终不发光,可能是R1阻值过大 |
C.适当减小R5阻值,可降低充电下限电压 |
D.适当增大R3阻值,可提高充电上限电压 |
同类型试题
y = sin x, x∈R, y∈[–1,1],周期为2π,函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x, x∈[–1,1], y∈[–π/2,π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2
y = sin x, x∈R, y∈[–1,1],周期为2π,函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x, x∈[–1,1], y∈[–π/2,π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2