Series Switch AND - Electronic Circuits Step by Step

Series switches behave like AND because one open switch breaks the only path. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

Series switches share one path

In a series network, every switch on the path must be closed before the lamp has a conducting route.

\text{series path} \Rightarrow \text{all switches must close}

One open switch makes off

One switch is closed and the other is open, so the lamp is off.

\text{closed AND open} \Rightarrow \text{off}

Both closed makes on

When both switches are closed, the graph has a complete path and the lamp is on.

\text{closed AND closed} \Rightarrow \text{on}

Only one series row turns on

The full table has four graph states. Any open switch breaks the only path; only both closed turns the lamp on.

\begin{array}{c|c|c}A&B&\text{lamp}\\\text{open}&\text{open}&\text{off}\\\text{open}&\text{closed}&\text{off}\\\text{closed}&\text{open}&\text{off}\\\text{closed}&\text{closed}&\text{on}\end{array}