It often has a transition frequency of around 3. The frequency at which gain begins to drop off may be much lower, see below. Maximum Ratings[ edit ] The maximum collector-to-emitter voltage for the 2N, like other transistors, depends on the resistance path the external circuit provides between the base and emitter of the transistor; with ohms a 70 volt breakdown rating, VCER, and the Collector-Emitter Sustaining voltage, VCEO sus , is given by ON Semiconductor. Sometimes the VCBO breakdown voltage the maximum voltage between collector and base, with the emitter open, an unrealistic arrangement in practical circuits is given as the only voltage rating, which can cause confusion. The total power dissipation written PD in most American datasheets, Ptot in European ones depends on the heatsink to which the 2N is connected. The device is designed to operate with an efficient heatsink, but care must be taken to mount the device properly,    else physical damage or worsened power handling may result, especially with cases or heatsinks that are not perfectly flat.
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The rectified voltage at capacitor C1 is around So we need to use all the capacitors which are rated at 50v in the circuit. Pot RV1 allows us to vary the output voltage in between 0 to 28V. The minimum output voltage of LM voltage regulator 1. In order to get 0V at the output we are using 3 diodes D7, D8 and D9.
Here 2N transistors are used to get more current. Pot RV2 is used to set the maximum current available at the output. This regulator provides output voltage ranging from 1.
This IC is easy to use and requires only two resistors to provide the variable supply. It provides internal current limiting, thermal shut down and it provides more line and load regulation as compared to fixed voltage regulators. Because of all these features these IC is mostly used in variety of applications. Note This circuit is studied theoretically and may require some changes to implement it in practical.
Variable Power Supply Circuit from Fixed Voltage Regulator The fixed voltage regulator is used to offer fixed voltage at the output terminal and does not depend upon the input voltage supplied. Here is the circuit producing variable voltage Power supply designed using fixed voltage regulators.
Then the voltage is applied to the voltage regulator. Output of the regulator can be varied by varying the resistance connected to the common pin of the Imagine that the resistor which is attached between the com terminal and the output terminal of regulator has a value of ohm R1. This implies that the value of current is Among the rotary switch and ground there is some amount of standby current of 2.
Hence about Now assume that from the circuit we need 5V to 12V. With the regulator output we directly got 5V minimum. While if there is a need of 12V then between com and output 5V is available and for the rest 7V we need to select the appropriate value of the resistor.
2N2955 Datasheet, Equivalent, Cross Reference Search
The rectified voltage at capacitor C1 is around So we need to use all the capacitors which are rated at 50v in the circuit. Pot RV1 allows us to vary the output voltage in between 0 to 28V. The minimum output voltage of LM voltage regulator 1. In order to get 0V at the output we are using 3 diodes D7, D8 and D9. Here 2N transistors are used to get more current.
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Variable Power Supply Circuits