- The PiSquare Academy

Torques in Deflection-type Instruments

1 · Deflecting torque

Measured quantity (I)0.00

T_d ∝ (measured quantity). Produced by the current/voltage being measured. It drives the pointer away from zero. On its own the pointer would never stop.

Show scale (dial face)
Show target line

2 · Controlling torque

No controlling torque. Nothing balances the deflecting torque, so the pointer just keeps rotating — it never stops at a reading. This is exactly why a spring (or gravity) control is essential.

Mechanism (spring / weight)

3 · Damping torque

Damping strength (D)0.65

Damping symbols & motion

4 · Moving system

Inertia of pointer (J)1.00

Heavier moving parts (higher J) swing more slowly and overshoot more before settling.

Overlays

Torque arrows on pointer
Live torque bars
Deflection-vs-time graph

Live values

Deflection θ

0°

Final θ (steady)

0°

Damping ratio ζ

–

Behaviour

–

Tip: set damping to None to show why a pointer would oscillate forever, then switch on Air or Fluid to bring it to rest.