The dip meter is most directly applicable to:

A dip meter determines resonance by transferring a small amount of RF energy from its own oscillator coil into the circuit under test. It is most directly applicable to parallel tuned circuits (LC tank circuits) because their inductive coils readily couple with the dip meter's coil, absorbing energy at resonance and causing the meter to "dip." Series tuned circuits present a very low impedance at resonance and do not couple well magnetically with a dip meter in a way that produces a reliable reading. Digital logic circuits and operational amplifier circuits operate on entirely different principles (voltage levels and active signal amplification) and do not utilize passive RF resonant tanks that can be tested with a dip meter.