Slide-Wire Wheatstone Bridge
Purpose
Students observe how a Wheatstone bridge measures unknown resistance by adjusting a slide wire until the galvanometer nulls. Swapping plug-in resistors of different values shows how bridge sensitivity degrades when the ratio arms are poorly matched to the unknown.
Figure 1:
The complete demonstration Wheatstone bridge showing the slide wire along a calibrated ruler, the center-zero galvanometer, plug-in resistor positions at top, and battery power source.
Figure 2:
Close-up showing the slide wire, ruler scale, sliding contact, galvanometer connections, and battery.