Worked example: A galvanometer has resistance G = 100 Ω and full-scale deflection current Ig = 1 mA. (a) What shunt converts it to a 0–1 A ammeter? (b) What series multiplier converts it to a 0–10 V voltmeter? (c) What is the ammeter's resistance? Step 1: Ammeter — shunt S in parallel: at full scale, Ig·G = (I − Ig)·S → S = Ig·G/(I − Ig) = (0.001 × 100)/(0.999) ≈ 0.1001 Ω ≈ 0.1 Ω. Step 2: Voltmeter — multiplier R in series: V = Ig(G + R) → R = V/Ig − G = 10/0.001 − 100 = 9900 Ω ≈ 9.9 kΩ. Step 3: Ammeter resistance = G·S/(G + S) ≈ 0.1 Ω — desirably tiny, so inserting it barely changes the circuit current. Note the pattern: shunt ≈ G·(Ig/I), multiplier ≈ V/Ig.