This article shows DC simple three transistor amplifier.

Applications include:

- sensor amplification (biased or non biased),

- current amplification (amplification of current sources - transistors)

This circuit is useful for continuing a cascade of current amplification.

You can see the circuit working as touch switch this video at just 1 V:

Step 1: Design the Circuit

I drawn the circuit via https://easyeda.com online software:

A 1 kohm resistor is useful for limiting the transistor base current. Increasing the Rb value will reduce the circuit gain but will also reduce the circuit current consumption and reduce the chances of power supply oscillations. However, the video is showing that the circuit is working well.

Step 2: Make the Circuit

I did not use a soldering iron. I twisted the wires with pliers.

You can make this circuit on a piece of cardboard or plastic.

I used blue tack to attach the circuit to box. However, the circuit might still move if you shake the box fast. Thus better use screws, nuts and bolts. Also, you should secure wires to matrix board with cable ties or 1 mm metal wire to prevent wire damage due to opening and closing of the box.