There is always a voltage drop between the electrodes of a triggered gas-filled spark gap. It is shown that the magnitude of this voltage, its form and frequency, can have a dramatic effect on the damping of a triggered RLC circuit. Energy can be fed to such an oscillating circuit by externally controlling the frequency of the spark gap voltage drop waveform. The dependence of this energy transfer on the amplitude, frequency and polarity of the gap voltage drop is examined experimentally and theoretically with the aid of numerical calculations. The conclusions of this study are applied to reducing the damping influence of a spark gap and to the construction of a circuit to generate pulses of RF oscillations.