Calculate Collector Current w/ Emitter @ 100mA - Transistor Switch

In summary, the conversation is discussing a question about calculating the collector current and maximum voltage across a resistor in a circuit involving a N-P-N type transistor, a functional siren, a thermistor, and two resistors with unknown values. The participants in the conversation also mention the importance of understanding the operation of a bipolar junction transistor and its beta parameter in order to solve the question.
  • #1
Jason7fd
3
0

Homework Statement


http://img300.imageshack.us/img300/2640/17569077cy5.jpg
The transistor is a N-P-N type. When the siren is functional, the resistance of thermistor is 120 ohm. R1 is 600 ohm. The question is "Calculate the collector current if the emitter current is 100mA". I know that current of emitter = current of collector + current of base, but how do I find the base current? Another one, "what is the maximum voltage across R1 if the siren is functional?".

Homework Equations


none


The Attempt at a Solution


none
 
Last edited by a moderator:
Physics news on Phys.org
  • #2
You didn't provide the value of R2. Also you didn't specify which end of the BJT is the emitter or collector. Is the BJT functioning in forward-active mode?
 
  • #3
Defennder said:
You didn't provide the value of R2. Also you didn't specify which end of the BJT is the emitter or collector. Is the BJT functioning in forward-active mode?
I hav updated the schematic diagram. Sorry, I am not sure what are BJT and forward-active mode. The value of R2 is not provided in this question.
 
  • #4
Uh, how are you expected to do this question if you don't know how a bipolar junction transistor (BJT) works in circuits? Do you know the equation for collector current in terms of VBE? What is value of B, the beta parameter of the BJT?
 
  • #5
Defennder said:
Uh, how are you expected to do this question if you don't know how a bipolar junction transistor (BJT) works in circuits? Do you know the equation for collector current in terms of VBE? What is value of B, the beta parameter of the BJT?
I wish I was taught about this in school but they are not in the syllabus. It is a question from O-level Physics of Malaysia.
 
  • #6
Hi, could you post the question exactly as it is ? Because what you have provided so far is insufficient.
 

FAQ: Calculate Collector Current w/ Emitter @ 100mA - Transistor Switch

What is a transistor switch?

A transistor switch is a type of electronic switch that uses a transistor to control the flow of electricity between two parts of a circuit. It can be used to turn a circuit on or off, or to amplify or invert a signal.

How do you calculate collector current with emitter at 100mA?

To calculate the collector current with the emitter at 100mA, you will need to use the formula Ic = (β x Ib) + Ie. β (beta) represents the current gain of the transistor, Ib is the base current, and Ie is the emitter current. Assuming β = 100, if the emitter current is 100mA, then the collector current will be 10A.

What is the purpose of calculating collector current with emitter at 100mA?

Calculating the collector current with the emitter at 100mA is important because it helps determine the amount of current that will be flowing through the transistor. This is essential in designing and analyzing circuits that use transistors as switches or amplifiers.

How do you use a transistor as a switch?

To use a transistor as a switch, it must be connected in either a common emitter or common collector configuration. In a common emitter configuration, the transistor is connected between the power supply and the load, and the base is connected to a control signal. When the control signal is high, the transistor allows current to flow through the load, and when the control signal is low, the transistor blocks the flow of current.

Can you explain the concept of saturation in a transistor switch?

Saturation in a transistor switch refers to the state in which the transistor is fully conducting and allows maximum current to flow through it. This occurs when the base-emitter junction is forward biased and the collector-emitter voltage is low. In saturation, the transistor acts as a closed switch, allowing full current to flow through the load.

Similar threads

Designing a +10V Supply with Transistors: A Practical Approach
Replies
1
Views
882
Transistor acting as a switch in closed circuit (with a thermistor)
Replies
4
Views
2K
What Is the Current Amplification Ratio in a Bipolar Junction Transistor?
Replies
4
Views
1K
Simulation of transistor switch circuit
Replies
5
Views
3K
Calculate resistance if the switch is closed 2 battery with different voltage
Replies
6
Views
3K
NPN BJT transistor: base voltage / emitter current
2
Replies
60
Views
13K
BJT transistor analysis: common emitter confusion
Replies
5
Views
2K
Calculating the amplification of a transistor
Replies
5
Views
2K
Finding R, I & V in an PLC output interface
Replies
6
Views
3K
Transistor as an amplifier (doubt)
Replies
3
Views
1K

Hot Threads

Recent Insights

Back
Top