I am trying to turn on battery supply through the collector of the transistor but it seems that the current is too low at the collector. So how can I increase current output.
I am supplying 5 volt to the emitter terminal and the base is connected to ground through a 2k ohm resistor. Here I am getting 4.2 v at collector end which is same as the battery voltage but my device is still not powering on.
I have very little knowledge in this matter so forgive me if i have made any mistakes.

 

What are you powering with the battery? You are supplying only about 2mA of current to the base. That will limit the amount of current the collector/emitter will conduct.
You need to know the approximate current consumed by the device you are powering. As a rule of thumb, approximately 1/10 of that amount of current is needed to saturate the transistor. Check the datasheet and make sure that the transistor can handle the collector and base currents you need for your switch.

 

Try changing the 2k to 1k and see if the 4.2V goes up a little.

 

What are you powering with the battery? You are supplying only about 2mA of current to the base. That will limit the amount of current the collector/emitter will conduct.
You need to know the approximate current consumed by the device you are powering. As a rule of thumb, approximately 1/10 of that amount of current is needed to saturate the transistor. Check the datasheet and make sure that the transistor can handle the collector and base currents you need for your switch.

Hi Keith, Thank you so much for helping me.
If I want 270mA-300mA as collector output current how much Resistance should I use at the base terminal?

 

Try changing the 2k to 1k and see if the 4.2V goes up a little.

Hi ronsimpson, The voltage is ok, what is need is to increase current drawn at the collector terminal, around 270mA - 300mA. Thanks.

 

We still do not know what the load on the collector is. The fact that you have what you say is enough voltage on the collector yet your load doesn't operate is a sign that we don't know enough.

You might need a capacitor from the collector to ground.

Also, what is the suffix to the part number?
B, C, or D. This suffix indicates the current gain of the transistor.

 

We still do not know what the load on the collector is. The fact that you have what you say is enough voltage on the collector yet your load doesn't operate is a sign that we don't know enough.

You might need a capacitor from the collector to ground.

Also, what is the suffix to the part number?
B, C, or D. This suffix indicates the current gain of the transistor.

Hi Mr. Cappels, Thank you so much. The suffix is D. The

 

Are you measuring the voltage with the load connected or with no load ?
For the transistor to saturate with a collector current of 300 mA you will need about 30 mA base current.
A 150 ohm base resistor should be about right.

Les.

 

Hi ronsimpson, The voltage is ok, what is need is to increase current drawn at the collector terminal, around 270mA - 300mA. Thanks.

I will rephrase the question. What is the Collector voltage with the load attached?

The only data sheet I can find is very poor. It looks like you need 5 times the base current to get the transistor to close well at 300mA. So reduce the base resistor to 1/5 of the 2k you are now using.

 

The current gain is not used when a transistor is a switch. Like most little transistors, the datasheet shows that it saturates when its base current is 1/10th its collector current. Then for a 300mA load the base current should be 30mA. The base-emitter voltage is about 1V when the base current is 30mA then the base resistor must be (5V - 1V)/30mA= 133 ohms. The max saturation voltage is about 0.4V then the load gets 4.6V or more.

What is a "5V" battery? Three AA alkaline cells produce 4.5V and four cells produce 6V. Is it a almost dead 6V battery?

 

I will rephrase the question. What is the Collector voltage with the load attached?

The only data sheet I can find is very poor. It looks like you need 5 times the base current to get the transistor to close well at 300mA. So reduce the base resistor to 1/5 of the 2k you are now using.

I will rephrase the question. What is the Collector voltage with the load attached?

The only data sheet I can find is very poor. It looks like you need 5 times the base current to get the transistor to close well at 300mA. So reduce the base resistor to 1/5 of the 2k you are now using.

Hi ronsompson, The Collector Voltage with load attached is currently 4.2 V but the current at the collector is 0.00 A. Ok I will try to use a 150 Ohm resistor at the base terminal as also suggested above by LesJones(Thanks).

 

Are you measuring the voltage with the load connected or with no load ?
For the transistor to saturate with a collector current of 300 mA you will need about 30 mA base current.
A 150 ohm base resistor should be about right.

Les.

Thanks LesJones, I will try replacing the 2k Ohm resistor at the base terminal with a 150 Ohm resistor. Thanks

 

The current gain is not used when a transistor is a switch. Like most little transistors, the datasheet shows that it saturates when its base current is 1/10th its collector current. Then for a 300mA load the base current should be 30mA. The base-emitter voltage is about 1V when the base current is 30mA then the base resistor must be (5V - 1V)/30mA= 133 ohms. The max saturation voltage is about 0.4V then the load gets 4.6V or more.

What is a "5V" battery? Three AA alkaline cells produce 4.5V and four cells produce 6V. Is it a almost dead 6V battery?

Hi Audioguru, Thanks for the explanation. I have used a 3.7V 2200mAh Li-ion cell,
Link : https://www.amazon.in/Rechargeable-...ah+lithium+ion+battery&qid=1629390353&sr=8-13

 

How can your "3.7V" battery produce 5V??
The battery is Lithium-Ion rechargeable. Is it fully charged to 4.2V?
What is your load that draws no current when powered with 4.2V? Does the load work when it is connected directly to the battery?
Google never heard of Exme battery company in India. Is the battery a fake?