calculating resistor values for transistor biasing

#Calculating resistor values for transistor biasing download#

More advanced users however, may want to estimate the total output noise. For most designs, this will be all that is needed. You may need to iterate back and forth between these two first worksheets until a satisfactory solution is found. Since the exact resistor values are normally not available, the second worksheet 'R Given' allows the user to enter standard resistor values and see in turn how these affect the 'real' biasing point. Usually a transistor amplifier stage is designed starting with some biasing conditions from which the initial resistor values will be derived. The 'About' worksheet outlines the three main steps assumed in the design (see Figure 2). The following sections describe each of them, Look at this article as the spreadsheet 'User Guide'. The spreadsheet is divided into four main 'worksheets' (bottom tabs) each with a different purpose.

UPDATE: Added an Excel 2003 compatible version as some users can't open the latest excel formats.

#Calculating resistor values for transistor biasing download#

The spreadsheet can be download through the link below: I decided to share this spreadsheet in this article in hopes it will help other Electronics enthusiasts in these same tasks. The spreadsheet started as a simple resistor value calculator (given a bias point) and later evolved to include some more advanced features such as noise estimation. The overall gain of such a stage is actually surprisingly well stabilized against transistor Beta.īecause this is a circuit I use frequently, I decided to make an Excel spreadsheet to ease the calculations. However, the scheme is stable enough for many practical applications and has the advantage of only requiring two resistors: the collector resistor RC, and a feedback resistor Rf. A classic 'four-resistor' biasing generally offers better stability over temperature, transistor process and power supply variations.

The biasing scheme in Figure 1 is certainly not the most stable of the possible schemes. An Excel-based transistor amplifier calculator.įor simple Do-It-Yourself amplifiers such as the one described under my Karaoke Mixer project, I often turn to the circuit topology in Figure 1.