It has two heat-sensitive thermocouples or thermistors. Negative temperature coefficient (NTC) thermistors and fixed resistors are often used to limit inrush current. Inrush limiting resistors are much cheaper than thermistors. For such applications thermistors, silicon bandgap temperature sensors and resistance thermometers are more suitable. The regulator consisted of a network of rectifiers, diodes, resistors and two thermistors. Typical sensors include compasses, depth sensors, sidescan and other sonars, magnetometers, thermistors and conductivity probes. Key types of skin-surface thermometers include infrared thermometers and thermistors. Resistance thermometers and thermistors are generally used in two ways. Lower dosage of doping is used in other types (NTC or PTC) thermistors. Unlike ceramic PTC thermistors, silistors have an almost linear resistance-temperature characteristic. These probes consist of a pair of battery-powered thermistors mounted in a fine copper tip. This equation is used to calibrate thermistors. However, thermistors have a smaller temperature range and stability. Most of the heating elements are thermistors, they increase the resistance with the temperature. The dynamics of PTC thermistors being powered also is extremely useful.