The maximum junction to ambient thermal resistance is 200☌/W.The maximum junction to case thermal resistance is 83.3☌/W.The maximum power dissipation is 625mW (at above 25☌- 5mW/☌).The maximum collector to base voltage (VCB) is 25 Volts.The maximum collector to emitter voltage (VCE) is 25 Volts.The maximum continuous collector current (Ic) is 1.2 Amps.The maximum Emitter to Base voltage (VBE) is 1.5 Volts.The typical value of DC current gain (hfe) is high – 20,000 (minimum) and 70,000 (maximum) collector current Ic = 100 mAmps.It is an NPN type of Darlington transistor available on the To-92 package with 3-pins-Emitter, Base, and Collector.The following are the technical features or technical specifications of a 2N5306 NPN Darlington transistor. Pin 3: (Collector): This pin refers to a collector pin or terminal, which is connected to load.Pin 2: (Base): This pin refers to the base pin, which is used to switch the transistor ON or OFF.Pin 1: (Emitter): This pin refers to an emitter pin, which is generally connected to the ground to drain out the current flowing through the transistor.The 2N6306 NPN Darlington Transistor pin configuration/pin diagram is illustrated below. The main drawback of the NPN Darlington transistor is the high base voltage of around 1.5 Volts. The maximum current allowed to pass through it is up to 1.2Amps, which helps to use in ideal applications of high current. The 2N5306 is normally called an NPN Darlington transistor with a current gain of around 20000, which makes it very easy to use in amplifier applications. In this case, the Darlington transistor is used. In some applications, the base current is limited and can’t be increased to increase the gain of the transistor. When the load requires high power, it is necessary to increase the base current of the transistor. Load Current = Input Current x Transistor Gain The formula of load current when the transistor is in ON condition is, When the input current is applied to the base terminal of the transistor, then it is turned ON to allow the flow of the load current. It shows the amplification of load current based on the input current of the base terminal. As you can see, when the collector current increases, h FE decreases.The main specification of the NPN Darlington transistor is its high current gain and high collector current (continuous). The graph above shows h FE on the y-axis and collector current on the x-axis for a general-purpose transistor. Students often find it difficult to visualise the relationship between h FE and collector current. The h FE parameter is not a constant though, because a transistor may have many ratings for different collector currents Ic. Hence, the current flowing through the collector is proportional to the base current multiplied by gain, as shown by the formula below. How large this current flow is depends upon a gain factor known as "h FE", also sometimes called the DC current gain, and beta. Remember that a bipolar transistor is a current amplifier, because a small amount of current "Ib" through the base controls a larger amount of current "Ic" flowing through its collector. For hard saturation, engineers usually choose a value of 10. Value for transistor switching purposes we always choose the minimum rating as the worst case because we want the transistor to conduct in the saturation region. The parameter "h FE" represents the DC gain,Īnd this is the parameter to consider. Small case "h fe" represents the small-signal current gain or AC gain,Īnd we do not use this parameter when using the transistor as a switch. In transistor literature, there are two different types of gain parameters with the same three letters. There are two calculators in this multi-page section of the article, and the first one is for when the load resistance is known, whilst the second, is for when the load current is known. A proper value of base resistance is therefore required for conduction in this region, and this value is different for different input switching voltages. In these types of switching applications, we require the transistor to behave as a switch and conduct fully in For hard saturation, engineers usually use a DC current gain h FEĪn NPN transistor requires a positive voltage at the base junction to switch ONĪnd control a load (RL) such as a low-voltage relay with a known resistance value. This resistor determines the amount of saturation current I b(sat) flowing into the base junction, and that controls the amount of saturation current I c(sat) flowing through the collectorĪnd emitter junctions. Engineers often have to consider the required value of the base resistor that controls the amount of current entering the base junction of a bipolar junction transistor (BJT) to cause it to conduct in the saturation region.
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