That depends on the type of thermistor
Some solid state thermistors are only able to run on one correct polarity and so are direct current.
Other thermistors designed as simple heat variable resistors can run on both direct current and alternating current.
I hope you mean the thermistor. If so,well it does not obey Ohms law. When current flows through the thermistor its temperature start increasing which reduces the resistance of the thermistor. A reduction in resistance at the same supply voltage will cause the current to increase. Thus it's not obeying Ohms law.
V=IRR changes as a result of the change in temperature.
direct current.
The symbol of a thermistor is a resistor with an arrow pointing towards it.
A thermistor changes its resistance when the temperature changes. This means as the room temperature changes the current in the circuit containing the thermistor changes. This change in current is detected by the heater circuit, turning the heater on and off.
There is only one type of direct current and its 'frequency' is zero.
direct current
Alternating current. Direct current is used in batteries.
direct current
A RV absorption refrigerator uses a thermistor as a thermostat. The thermistor is moved up or down to regulate the refrigerator temperature.
Alternating current is better than direct current for transmission.
The battery in an automobile furnishes direct current.