On another part of this project, I use the light bars as level meters, and each separate LED is controlled via a shift register, thus the separate resistor. I had mentioned in a comment in an answer below that I was using a 330 ohm resistor with each LED. The LEDs come in the form of this LED light bar array (or at least very similar). I am using an external power supply that is wired into a custom board with a 5v voltage regulator so I am powering the LEDs directly from this regulator. Is this the approach I want to take? I presume I would need a higher power transistor? I don't want individual control, I just want to be able to turn them all on or all off. If you are designing a PCB or Perf board with this component, then the following picture from the 2N3904 transistor Datasheet will be useful to know its package type and dimensions.I want to be able to turn on 50 red LEDs with one pin of an Arduino. Commonly used in TV and other home appliances.VCB and VBE is high hence can be used to control voltage loads up to 40V.Amplifier modules like Audio amplifiers, signal Amplifier etc.Driver Modules like Relay Driver, LED driver etc.When uses as an Amplifier the DC current gain of the Transistor can be calculated by using the below formulaeĭC Current Gain = Collector Current (IC) / Base Current (IB) Of the above types, common emitter type is the popular and mostly used configuration. Some of the configurations used in amplifier circuits are: ![]() It can amplify power, voltage and current at different configurations. The value of IB should not exceed mA.Ī Transistors acts as an Amplifier when operating in Active Region. Where, the value of VBE should be 5V for 2N3904 and the Base current (IB depends on the Collector current (IC). ![]() The value of this resistor (RB) can be calculated using below formulae. Anything more than 5mA will kill the Transistor hence a resistor is always added in series with base pin. As mentioned the biasing current should maximum of 5mA. ![]() As discussed, a transistor will act as an Open switch during Forward Bias and as a closed switch during Reverse Bias, this biasing can be achieved by supplying the required amount of current to the base pin. When a transistor is used as a switch it is operated in the Saturation and Cut-Off Region as explained above. When base current is removed the transistor becomes fully off, this stage is called as the Cut-off Region and the Base Emitter voltage could be around 600 mV. This stage is called Saturation Region and the typical voltage allowed across the Collector-Emitter (VCE) or Collector-Base (VCB) could be 40V and 60V respectively. When this transistor is fully biased then it can allow a maximum of 200mA to flow across the collector and emitter. To bias a transistor we have to supply current to base pin, this current (IB) should be limited to 5mA. The maximum amount of current that could flow through the Collector pin is 200mA, hence we cannot connect loads that consume more than 200mA using this transistor. 2N3904 has a gain value of 300 this value determines the amplification capacity of the transistor. Note: Complete Technical Details can be found at the 2N3904 datasheet given at the end of this page.īC549, BC636, BC639, 2N2222 TO-92, 2N2222 TO-18, 2N2369, 2N3055, 2N3906, 2SC5200ĢN3904 is a NPN transistor hence the collector and emitter will be left open (Reverse biased) when the base pin is held at ground and will be closed (Forward biased) when a signal is provided to base pin.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |