How to apply NTC thermistor 1

NTC components are thermistors with negative temperature coefficients, which are widely used in amateur radio production. The following mainly introduces three applications:

1) Temperature compensation in instrument circuits

In instrument circuits, there are many components made of metal wires, similar to wire wound resistors. Metal wires generally have a positive temperature coefficient, and using NTC thermistors with a negative temperature coefficient for compensation can offset errors caused by temperature changes. Figure 1 shows a temperature compensation circuit. It is to parallel the NTC thermistor with a manganese copper wire resistor with a very small temperature coefficient of resistance, and then connect it in series with the compensated component to achieve temperature compensation.diode,

Figure 1 Application of NTC Thermistor in Instrument Temperature Compensation

2) TC is used to stabilize the operating point in transistor circuits

Figure 2 shows the circuits for stabilizing the operating points of three types of NTC thermistors and transistors.

Figure 2 (a) shows a simple transistor current amplifier, with an NTC thermistor RT added to the base circuit. When the ambient temperature changes, the output current of the circuit also changes. Increasing the NTC can automatically adjust the collector DC current of this stage transistor, stabilizing the output gain of the transistor.diode