Table of Contents
How does BJT temperature sensor work?
Temperature sensors are easily produced with semiconductor processing technology by using the temperature characteristics of the PN junction. When constant current passes through the base-emitter junction it produces a voltage between the base and emitter (Vbe) that is a linear function of the absolute temperature.
What sensor is used for temperature?
Non-contact temperature sensors are usually infrared (IR) sensors. They remotely detect the IR energy emitted by an object and send a signal to a calibrated electronic circuit that determines the object’s temperature.
Which material is used in temperature sensor?
A thermistor is a special type of resistor which changes its physical resistance when exposed to changes in temperature. Thermistors are generally made from ceramic materials such as oxides of nickel, manganese or cobalt coated in glass which makes them easily damaged.
Are temperature sensors transistors?
Using 2N2222 as Temperature Sensor The transistor is used like a temperature sensor probe which must have a appropriate housing like a vintage voltmeter probe grip, a small section of metal tube, and so on.
What is digital thermal sensor?
A digital temperature is a sensor, which provides 9-bit temperature readings. Digital temperature sensors offer excellent precise accuracy, these are designed to read from 0°C to 70°C and it is possible to achieve ±0.5°C accuracy. These sensors completely aligned with digital temperature readings in degrees Celsius.
How are temperature sensors used in motors?
As mentioned, temperature sensors are commonly used to prevent overheating and ensure that motors remain UL 1446 compliant. To this end, some manufacturers install temperature sensors or switches inside the motor that cut power from the drive when the winding approaches its maximum allowable hotspot temperature.
Is the NPN transistor a temperature sensor?
4 Answers. TMP36 is specifically a temperature sensor, not an NPN transistor like the 2N2222. You might have them confused because they both can come in TO-92 package.
Which transistor is used as sensor?
You can use a regular BJT as a temperature sensor by measuring Vbe; Vbe has a -2.2mV/C tempco. I used this years ago to measure the thermal resistance junction to ambient for pass transistors in a phone battery charger.
How to measure the case temperature of a BJT?
The base-emitter junction of a BJT has a very predictable transfer function that is dependent on temperature. So, in order to measure the case temperature of a device or board temperature, we can use a discrete NPN (or PNP) transistor as shown in the next figure.
Can a transistor be used as a temperature sensor?
Since the base-emitter junction of any transistor is also a diode, it’s easy to use discrete transistors as robust temperature sensors.
Can a diode be used as a temperature sensor?
Temperature Sensor Diode – Forward It’s worth noting again that a diode can be used as a temperature sensor, and most diode-based temperature sensors use the change in forward voltage. This is because the relationship is fairly linear with about 2mV less voltage drop for every degree increase of temperature (-2mV/°C).
What is the sensitivity of the fabricated temperature sensor?
For a temperature range from 0 to 125°C, the fabricated temperature sensor has the sensitivity of °3.39°mV/°C or so with linearity up to 99.996°. Simulated VEB and VSG versus temperature, their linear regression lines and nonlinear deviation.