A vibration test rig must be excited at a frequency of using a series RLC circuit…
PHYSICS · Multi-part · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
A vibration test rig must be excited at a frequency of 1.0kHz using a series RLC circuit supplied with 100V rms. The resistor is 30Ω. Inductors available for use have a nominal inductance of 50mH but can vary by ±5% from their stated value. The designer wants the circuit to remain within ±1% of resonance despite this tolerance.
(a) Calculate the nominal capacitance required to tune the circuit exactly to 1.0kHz when L=50mH.
(b) Considering the ±5% tolerance in L, determine the maximum and minimum values of capacitance that will keep the circuit within the specified ±1% frequency band around 1.0kHz.
(c) Using your results, comment on whether a single fixed capacitor will suffice or if an adjustable capacitor would be preferable for this application.