Abstract: A pulsed thermal liquid level detector system is disclosed. The system includes a probe having a thermistor and a resistor disposed therein. The thermistor is thermally coupled to the resistor and is thermally coupled to a predetermined external surface of the probe by way of a material of low thermal resistance and capacity. The resistor is electrically coupled to a source of pulses which act to dissipate energy in the resistor thereby to heat the thermistor in accordance with the level of the pulses. The resistance of the thermistor varies in accordance with the temperature excursions induced by the pulses and within a range determined by the thermal capacity of the thermistor. The effective thermal capacity of the thermistor increases when the predetermined external surface is thermally coupled to a liquid which therefore reduces the resistance excursions of the thermistor.