type: | topic: instruments, optics, electrical
Diagram 1: Vernier Caliper (Schematic)
Main Jaw Vernier Scale Depth Probe Vernier Caliper — Key Parts Main ScaleLabel Table: Vernier Caliper Parts
| Part | Function |
|---|---|
| Main jaws (outside) | Measure external diameter / width |
| Inner jaws | Measure internal diameter (inside tube) |
| Depth probe | Measure depth of holes, steps |
| Main scale | Gives MSR in mm |
| Vernier scale | Gives fractional reading (n × LC) |
| Locking screw | Fixes jaws at reading position |
| Zero mark | Reference for zero error detection |
Diagram 2: Metre Bridge Circuit
A B R S J (Jockey) G Battery E + K Metre Bridge Circuit (R/S = $\frac{l}{100−l}$) ← l → ← 100−l →Label Table: Metre Bridge
| Component | Role |
|---|---|
| 100 cm resistance wire AB | Ratio arm of Wheatstone bridge |
| R (left gap) | Known resistance |
| S (right gap) | Unknown resistance to be found |
| Jockey J | Slides along wire to find null point |
| Galvanometer G | Detects zero current (null condition) |
| Battery E + key K | Drives current through the bridge |
| l | Balance length from A; used in R/S = |