I need a simple circuit to test a 2n3055 transistor

near 0.2 volt) when we need to make the transistor ON (switch ON) and into its cut-off region when we need to make the transistor OFF (switch OFF).

When we operate transistor as the class A common emitter amplifier usually we choose to bias the transistor (apply voltage on V BE and V CE) in such a way (Q-Point) that I C and V CE (output) will swing to its maximum or minimum value without any distortion (swing into the saturation or cut-off region) when the I B (input) swing to its maximum or minimum value but when we operate the transistor as switch we intentionally push the transistor into its saturation region to get the lowest possible V CE (i.e. One of the famous diagrams that show the transistor operating state is called the transistor static characteristic curve as shown on this following picture: Therefore to use transistor as a switch we have to make transistor OFF which equivalent to the logical вЂњ 0вЂќ and SATURATE which is equivalent to the logical вЂњ 1вЂњ. This is the type of state that we are looking for on this tutorial.ДЇrom the picture above we could see the voltage and current condition of transistor on each state if you notice when transistor is in off state the voltage across collector and emitter terminal is equal to the supplied voltage, this is equivalent to the open circuit and when transistor is in saturate state the collector to emitter voltage is equal or less then 0.2 Volt which is equivalent to the close circuit. We never use this state to run the transistor as a signal amplifier (class A amplifier) because the output signal will be clamped when the transistor is saturate. On saturate state: in this state any changes in I B will not cause changes in I C anymore (not linear) or we could say I C is nearly constant.For example if we have a transistor with gain of 100 and we increase the I B from 10uA to 100uA this will cause the I C to swing from 1000uA to 10000uA (1 mA to 10 mA). This type of state is suitable when we use transistor as a signal amplifier because transistor is said is in the linear state. On active state: in this state any changes in I B will cause changes in I C as well or I C = I B x h FE.Off state: in this state there is no base current applied or I B = 0.Therefore transistor can be used as amplifier any small signal (very small current) applied to the base terminal will be amplified by the factor of h FE and reflected as a collector current on the collector terminal side.ДЄll the transistors have three state of operation: The transistor actually works as a current gainer any current applied to the base terminal will be multiplied by the current gain factor of the transistor which known as h FE. I have to make clear on this BJT type to differentiate among the other types of transistors family such as FET (Field Effect Transistor), MOSFET (Metal Oxide Semiconductor FET), VMOS (Vertical MOSFET) and UJT (Uni-Junction Transistor).

One of the popular method is to use the Bipolar Junction Transistor (BJT) or we just called it transistor in this tutorial. Most of microcontrollers work within 5 volt environment and the I/O port can only handle current up to 20mA therefore if we want to attach the microcontrollerвЂ™s I/O port to different voltage level circuit or to drive devices with more than 20mA we need to use the interface circuit. Using Transistor as a Switch Decemby rwb, under Electronics.

I need a simple circuit to test a 2n3055 transistor