LRC Demonstrator - Physics Demonstrations - LRC Demonstrator | Physics Undergraduate Labs

Purpose

Demonstrate resonance in a series RLC circuit. Sweep frequency through resonance while the oscilloscope shows voltage and current becoming in-phase and current amplitude peaking when $$X_L = X_C$$ .

Full LRC demo setup: wire spool inductor, LCR board with transparent component enclosures and light bulb on wooden base, function generator, and oscilloscope showing two sinusoidal traces

Same LRC setup from slightly different angle, oscilloscope showing two phase-shifted sinusoidal traces

Handwritten circuit schematic labeled "Resonant LRC Circuit" showing C = 8 μF, L = 6.5 H max, R = 20 Ω, source at 72 Hz 10 V, with Channel 1 measuring voltage and Channel 2 measuring current

LRC setup with oscilloscope showing two nearly in-phase sinusoidal traces, indicating near-resonance condition

LRC setup with oscilloscope showing two sinusoidal traces with significant phase offset, indicating off-resonance condition

Close-up of LCR board showing transparent component enclosures, binding posts, banana plug wiring, function generator, and wire spool inductor with label "Slide knob over to change inductance"

Figure 3: Complete setup: LCR board with wire spool inductor, light bulb indicator, function generator, and oscilloscope displaying voltage and current waveforms.

Figure 4: Off-resonance: visible phase difference between voltage and current traces on the oscilloscope.

Figure 5: Handwritten schematic: C = 8 μF, L = 6.5 H (max), R = 20 Ω, driven at 72 Hz / 10 V. Ch 1 measures voltage, Ch 2 measures current.

Figure 6: Near resonance: voltage and current traces are nearly in phase, and current amplitude is at maximum.

Figure 7: Off-resonance: significant phase shift between voltage and current. Capacitive or inductive reactance dominates.

Figure 8: Close-up of the LCR board. Transparent enclosures show component construction. The inductor has a sliding knob to adjust inductance.

LCR Board

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