# Analog amplifier circuit

I've the following analog amplifier:

simulate this circuit – Schematic created using CircuitLab

The Vin is the input voltage of the amplifier and the V- system and the V+ system are the two points where I can controll the motor with the amplifier.

The questions I've are:

1. Has this amplifier a specific name?;
2. I think that the resistor R1 is a resistor to limit the current, but how does it do that?;
3. I think that R2 is a resistor to controll the voltage at the input of the voltage follower, but I can I caluclate that volateg?
• seems to be a homework question. You should at least try to come to a solution yourself and tell us where you are stuck/ what you do not understand. – Sir Sy May 31 '18 at 7:16
• @SirSy It isn't a homework question. And I set my thoughts in the question (like that I think that R1 is a resistor to limit the current). – asd May 31 '18 at 7:17
• It is a Darlington transistor. – Sir Sy May 31 '18 at 7:35

It's a voltage controlled current sink. Vin is a demand voltage and the transistors turn on sufficiently to take a current through the load that equals $I_{LOAD}\times R_2$.