I tried this with a single diode-connected BJT (base connected to collector) with a 10K resistor to the regulated (and otherwise unused) 3.3V rail on an Arduino Nano. Unfortunately, the sensitivity is reduced by at least an order of magnitude so better analog circuitry is required. Using matched transistors or multiple (2 or 3) currents with a single transistor allows cancellation of many of the transistor parameters that vary from unit to unit, as well as connection resistance. There are much better ways to measure temperature with a transistor, however the complexity is increased. With a 10-bit ADC and 5V Vref the resolution is about 0.5☌, which is adequate for many purposes. The current drops as the voltage increases (due to the use of a simple resistor as a current source) so the linearity isn't great= 11.2mV/K average at 0.25☌ and 10.5mV/K average at 75.100☌, but for narrow excursions around room temperature it should be fine, or it can be corrected digitally. Or just use an op-amp.Įdit: Here is a simulation result used as a simple Vbe multiplier. If you connect it as a Vbe multiplier, say with 5:1, and average many measurements you might be able to get a usable resolution of about 0.5☌. Sensitivity will be about -2mV/K so with a 5mV resolution ADC you’ll have 2.5 degrees C resolution, not great. It will require calibration (say at room temperature and 0☌ in an ice-water slurry. Please note that the Minimum Order Value is INR 500 for COD orders.If you connect the transistor as a diode and bias it with a reasonable current, maybe a couple hundred uA, you can read the voltage. Please contact to our support team at for any question related to shipping. For Cash on Delivery orders INR 80 will be charged for orders below INR 599 and INR 30 will be charged for the orders above 599. We ship to all over India with free shipping on all prepaid orders above 500. Returns are accepted only with 3 days from the date of delivery. Please read the product specifications and datasheet before selecting and ordering a product. Moreover we don't accept the return, if the ordered product is not fit for any specific application. We don't accept the returns for the products damanged by improper use of the product. If your item looks different from what is shown in the image on our website, we will take the item back and provide a refund or replacement as per your choice. Once our support team accept the return, we will provide a replacement or a complete refund including the return shipping cost. If you receive a product damaged during shipment, please notify us within the 3 days of you receive the product, supported by the proper pictures and description. Below are the conditions where we can accept a return request. Raspberry Pi based project 2N2222A NPN BJTĭue to the type of products we sell, we accept limited returns. To use it as a Switch or amplifier, you just have to forward bias Base Emitter Junction but care should be taken to limit the base current as emitter can only allow up to 800mA of the current to power the device. The 2N2222A is very much similar to BC547 BJT and 2N3902 BJT except it can allow more current than BC547 and can dissipate 652mW of power. Collector-Emitter Voltage (V CE) is 40V.Continuous Collector current (I C) is 800mA.It can be used in switching applications with current up to 800mA, in speed control of motors, also it can be used in Darlington Pair. To bias a transistor, we have to supply current to base pin, this current (I B) should be limited to 5mA. The maximum amount of current that could flow through the Collector pin is 800mA, hence we cannot connect loads that consume more than 800mA using this transistor. 2N2222A has a gain value of 110 to 800, this value determines the amplification capacity of the transistor. they will start conducting as BJT will operate in Saturation Region. As it is an NPN transistor, so collector and emitter will be left open when no signal is at the base and when a signal is provided to the base terminal, then the emitter and collector will be closed i.e. The 2N2222A is a common NPN Bipolar Junction Transistor (BJT) is used for general purpose low power amplifying or switching actions.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |