How do I choose a PTC thermistor?
For example, PTC thermistors for motor control may be specified at a high temperature with a close tolerance, whilst the tolerance below the switch temperature, being of less importance, is much greater. PTC thermistors for current limiting applications are, in most instances, specified in terms of current and voltage.
How would we use the PTC thermistor for overcurrent protection in power system?
Applications of PTC thermistors for overcurrent protection PTC thermistors can effectively protect motors from such overcurrent. For example, if the side mirror of a car is blocked by an object, the motor will lock when an attempt is made to set the mirror or retract it.
What is PTC temperature?
PTC stands for “Positive Temperature Coefficient”. PTC thermistors are resistors with a positive temperature coefficient, which means that the resistance increases with increasing temperature. PTC thermistors are divided into two groups based on the materials used, their structure, and the manufacturing process.
How does the PTC thermistor protect a circuit?
When connected in series with the input of an electrical or electronic circuit, such as a small motor or power supply, the PTC thermistor acts as a self-resettable fuse, protecting the circuit against current, voltage and temperature overload conditions.
What are the advantages of NTC thermistors?
NTC thermistors are used as ICLs (inrush current limiters) to protect circuits of electrical and electronic devices against inrush currents easily and effectively. Advantages of NTC thermistors NTC thermistors are temperature-dependent resistors that employ special semiconductor ceramics with a negative temperature coefficient (NTC).
How does a Positive Temperature Coefficient thermistor work?
When the previous scenarios occur, a positive temperature coefficient (PTC) thermistor can provide effective inrush current protection. A PTC thermistor functions opposite to an NTC thermistor: as temperature rises, its resistance increases.
How does a PTC-based current limiting circuit work?
A PTC-based limiting circuit requires a bypass circuit to send current back through the PTC thermistor to protect the system against shorts. By setting the bypass to 3 or 4 times the amount it takes for the inrush current to settle, response time for the PTC-based limiter is extremely fast.