Here are the safe operating guidelines to get good stable and long term performance with this transistor. Safe Operating Guidelines / Absolute Maximum Ratings: Moreover, it is not only limited to these uses and can also be used in other applications such as switching, etc.Īudio Amplifiers such as guitars and other audio amplifiers Other than that it can also be used in amplifier circuits. For example, it can be used in circuits that require high voltage. The transistor is designed to use in many applications such as low current inverters with high voltage, switching regulators.ĢN3439 can be used in many applications. The transistor is having quite interesting specs such as collector to emitter voltage is 350V, collector to base voltage is 450V, max emitter to base voltage is 7V, max collector current is 1A, and total device dissipation is 5 Watts at 25☌. This high collector to emitter voltage makes it suitable to be used in many applications such as inverters, regulators etc. The transistor contains many features such as high collector to emitter voltage of upto 350V. Max Storage, Operating & Junction temperature range: -65 to +200 CentigradeĢN3439 Transistor Explained / Description:ĢN3439 is a TO-39 metal can package transistor that is built to use in commercial and home equipment and appliances.Minimum & Maximum DC Current Gain (hFE): 30 to 160.Max Collector Dissipation (Pc): 10 Watt.Max Collector-Emitter Voltage (VCE): 350V.Max Collector Current(IC): 1A or 1000mA.At a base current of 2mA this gives a value for R1 = 2200 ohms. (= 4.4V) because the base voltage is fixed at 0.6V. In the case of the common emitter with a 5V input R1 needs to drop 5 - 0.6 volts. ( In theory you may not even need a resistor but in the event of a short circuit load the maximum current into the base will be 88mA.) Lets say 4.9V at the base so R1 has to drop 0.1V 2mA. It has 5V at the input but we want as much voltage as possible at the base. In the case of the emitter follower the voltage drop needs to be a small as possible. That would give a value of 500/250 = 2mA for the base current. Suppose the load current is 500mA and the typical current gain of the transistor is 250. To calculate the value of R1 we use Ohm's law (V=IR) and the relationship between base and collector current for the transistor, Ic = current gain x Ib. The power dissipated by the transistor is minimal (Vsat * Ic). The rest of the voltage is dropped across the load. When fully turned ON the voltage across the transistor is the saturation voltage (Vsat) - typically about 0.1 - 0.3V depending on transistor type and collector current. In the case of the common emitter circuit the emitter voltage is FIXED at 0V and will limit the base voltage to 0.6V. This means the transistor will have to dissipate POWER (7.6 x Ic) and could get quite warm or possibly overheat. The transistor is not fully turned ON and the voltage across the transistor (Vce) will be 12 - 4.4 = 7.6V. In the case of the emitter follower circuit the voltage across the load can RISE until this condition (Vbe = 0.6V) is satisfied. For current to flow through the junction the base must be about 0.6V higher than the emitter. The base-emitter junction acts like any silicon diode ( its the 'PN' part of the NPN transistor). The transistors are actually acting in the same way. In this case there are two different (separate) circuits so R1 will have a different value in each. R1 is simply a label and may have different values in different circuits. The value of R1 sets the size of base current. If you use the common emitter circuit with the load between the collector and +12V you will get a voltage at the collector between 12V (transistor OFF) and 0.1V (approx) which is the saturation voltage (Vsat) when the transistor in turned ON. If you use the emitter follower circuit with the load between emitter and ground the maximum voltage across the load will be base voltage - 0.6V due to the base-emitter junction. Without a circuit diagram its impossible to answer the question specifically.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |