Before revision: Principle of operation 400px|Oscillator portion of a transistor-based gate-dip meter Central to the dip meter is a high-frequency variable-frequency oscillator with a calibrated tuning capacitor and matching interchangeable coils, as shown in the circuit diagram on the right .
After revision: Principle of operation 400px|Oscillator portion of a transistor-based gate-dip meter Central to the dip meter is a high-frequency variable-frequency oscillator with a calibrated tuning capacitor and matching interchangeable coils, as shown in the circuit diagram .