Another type of thermistor is a silistor, a thermally sensitive silicon resistor. Precision thermostats use a thermistor or silicon temperature sensor. Most have an internal thermistor or thermocouple or can be connected to external sources. The resistance of an NTC thermistor decreases as its temperature increases. The current and voltage across the thermistor depend on the particular circuit configuration. There are several advantage and disadvantages to using an NTC thermistor thermometer. Most electronic thermostats use either thermistor devices or integrated logic elements for the anticipation function. Another disadvantage is that the NTC thermistor is not short-circuit-proof. A common design uses an incandescent lamp or a thermistor in the feedback circuit. The temperature of the block is in turn measured by a thermistor. Low budget gauges do not have this compensating thermistor. A commercially viable thermistor was invented by Samuel Ruben in 1930. It is generally given for the thermistor in still air and in well-stirred oil. Thermistor elements are the most sensitive temperature sensors available.