What is it?

This 2 layer PCB is designed to analyse the effect of a simple common emitter amplifier that uses a BC108 transistor can. It is a fast and easy prototyping board that can be easily soldered due to sufficient spaces between components. Emitter resistors are used in this circuit to increase the gain stability. This board uses through hole components.

The circuit is designed to work with +10V DC which shall be connected to the 2 pin terminal (VDC). The input signal shall be connected to the 2 pin terminal (VIN). To view the wave forms, an oscilloscope shall be connected to the two pin terminal (VOUT). All positive and negative terminals are labelled.

This prototype board can be used with different values of components to experiment with as an example, I have added two images that shows the frequency, numerical gain, output voltage and dB gain for a CE amp with and without the decoupling capacitor. The input signal was set to 20mA p-p.

Components

• 2 Pin Terminal Block x3
• 1uF Polarised Capacitor x2
• 10uF Polarised Capacitor x1
• BC108 Transistor x1
• 470 Ohm Resistor x2
• 4.7k Ohm Resistor x1
• 18k Ohm Resistor x1
• 82k Ohm Resistor x1

NOTE: COMPONENTS ARE NOT SOLD WITH THIS PRODUCT.

Why did you make it?

I made this board as a starting point to understand the process of PCB design and manufacture.

What makes it special?

It is designed to help students analyse the behaviour of a CE Amplifier without the use of bread boards and fly leads.

High gain is sacrificed when using emitter resistors to stabilise the gain, therefore a capacitor is being used in parallel with the emitter resistors so that we can get good stability and high gains at high frequencies as the capacitor increases AC gain but does not affect DC feedback