This post explains for the transistor.
The Part Number is BF195.
The function of this transistor is 20V, 30mA, NPN Transistor.
Package: TO-92 Type
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BF195 is 20V, 30mA, NPN Transistor. A NPN transistor is a type of bipolar junction transistor (BJT) that consists of two n-type semiconductor materials separated by a single p-type material.
The NPN transistor is used to amplify or switch electronic signals and is widely used in many electronic circuits. It works by controlling the current flow between the collector and emitter terminals through the base terminal.
When a small current is applied to the base, it controls a much larger current between the collector and emitter, making the NPN transistor an effective amplifier or switch.
1. Forward Biased: In order to operate, the base-emitter junction of an NPN transistor must be forward biased, meaning that the base must be connected to a positive voltage relative to the emitter.
2. High Input Impedance: NPN transistors have a high input impedance, which means that they are less likely to draw current from the input source, and are therefore less likely to cause a drop in voltage across the source.
3. Inverted Output: NPN transistors are known for producing an inverted output relative to their input. That is, if the input signal is high, the output signal will be low, and vice versa. This behavior is due to the way the transistor is designed and is an important characteristic for many electronic applications.
Absolute maximum ratings ( Ta=25°C )
1. Collector to Base Voltage: Vcbo = 30 V
2. Collector to Emitter Voltage: Vceo = 20 V
3. Emitter to Base Voltage: Vebo = 5 V
4. Collector Current: Ic = 30 mA
5. Total Power Dissipation: Pd = 250 mW
6. Junction Temperature: Tj = 125°C
7. Storage Temperature: Tsg = -65 ~ +125°C