Hello!
I am a new member and I need some help with a very small and easy circuit.
In fact I want it to be as simple as possible.
I have a battery, 3.0V and 30mA, a LED ~ 3.0V and also 30mA.
My first question is: do I really need to put a resistor?
I want the circuit to be activated with a simple finger.
I saw that we can create a simple touch sensor with a Transistor NPN.
I also saw that we can increase the output of the transistor by using a Darlington Pair(but I tryed and didn't notice any difference)
When I power the LED with the simple battey, nothing more, this is working fine and the LED works pretty well.
When I put the transistor and my finger, it also works, but the LED bright much less, why?
I don't understand why the Transistor would drain some power or current? I am a total noob in electronics sorry.
My circuit looks like that but I don't use any resistor and my source power is 3V.
http://www.learningaboutelectronics.com/images/Touch_sensor_schematic.jpg
I precise that I am using a random NPN transistor, I just baught the first I saw, this is a BC547.
Does the light bright less because of the caracteristics of the transistor? Is there a transistor which correspond to my requirements?
I would like to activate the LED with a touch sensor like this, but I want the LED to bright as much as if I power it directly with the battery, is it possible?
I thought about temporary switch, but I really really want touch sensor.
If nobody can help me, do you think there is any other forum or person who can help me?
Thank you in advance.
PS: Escuse my english, this is not my nattive language.
Don't hesitate to correct me.
I am a new member and I need some help with a very small and easy circuit.
In fact I want it to be as simple as possible.
I have a battery, 3.0V and 30mA, a LED ~ 3.0V and also 30mA.
My first question is: do I really need to put a resistor?
I want the circuit to be activated with a simple finger.
I saw that we can create a simple touch sensor with a Transistor NPN.
I also saw that we can increase the output of the transistor by using a Darlington Pair(but I tryed and didn't notice any difference)
When I power the LED with the simple battey, nothing more, this is working fine and the LED works pretty well.
When I put the transistor and my finger, it also works, but the LED bright much less, why?
I don't understand why the Transistor would drain some power or current? I am a total noob in electronics sorry.
My circuit looks like that but I don't use any resistor and my source power is 3V.
http://www.learningaboutelectronics.com/images/Touch_sensor_schematic.jpg
I precise that I am using a random NPN transistor, I just baught the first I saw, this is a BC547.
Does the light bright less because of the caracteristics of the transistor? Is there a transistor which correspond to my requirements?
I would like to activate the LED with a touch sensor like this, but I want the LED to bright as much as if I power it directly with the battery, is it possible?
I thought about temporary switch, but I really really want touch sensor.
If nobody can help me, do you think there is any other forum or person who can help me?
Thank you in advance.
PS: Escuse my english, this is not my nattive language.
Don't hesitate to correct me.