I'm new to electric amplifier circuits and I'm trying to make one that will produce a 1A output (1A@3V) to a load from a 1mA input.
Here is what I thought of:

Will this circuit work or how should I properly design this?

 

The Tip120 is a Darlington with 1.4VB/E drop with an hfe of 1000,

So 3.7v-1.4v = 2.3V with a 1.2K base resistor is 1.9mA base current x hfe is 1.9A Collector current.

 

hi Dan,
You cannot increase the current by using a transistor connected in that way, you need 3V 1A power source.
The top of the load is connected to 0V!
E

 

hi Dan,
You cannot increase the current by using a transistor connected in that way, you need 3V 1A power source.
The top of the load is connected to 0V!
E
View attachment 165961

Oh so if I connect the load to from collector to emitter there won't flow current? (0V@0A)?

 

hi,
No current.!
A transistor cannot generate a current.
It can only control the current that is available from an external power supply.
E

 

If your circuit worked, it would be a source of free energy!

Bob

 

Maybe I can use a voltage follower op-amp to convert voltage to current and increase the current?

 

Maybe I can use a voltage follower op-amp to convert voltage to current and increase the current?

hi,
What is your power supply.?
E

 

If you only have 1mA at the input, then a logic-level N-MOSFET (designed for operation with a 3.3V input with a Vth max<2V) might be a better choice.
MOSFETs require essentially no input current.

 

Yes but as far as I understand a transistor must have additional power source (example: collector), hence 1A will still flow from the power source (lipo 3.7v@500mAh) as mentioned in #3
I 'm looking for a solution to avoid that.

 

I 'm looking for a solution to avoid that.

hi Dan,
Sorry I don't understand, avoid what.?
E

 

Yes but as far as I understand a transistor must have additional power source (example: collector), hence 1A will still flow from the power source (lipo 3.7v@500mAh) as mentioned in #3
I 'm looking for a solution to avoid that.

There is no free lunch, and there is no solution around that. You cannot create power from nothing, so if you want 3V*1A, which is 3W, then you have to provide the 3W at the input. From a battery, power supply or whatever else.

 

You can get 1A and 3V from a 1mA input, but the input voltage must be 3000V plus another 10 or 20% for losses.

You can also get 1A at 3V for 1 second from a 1mA 3V input if you let it charge a capacitor for 1000 seconds plus extra to cover losses.

What are you actually trying to do?

Bob