Transistor preamplifier help

[MSRuprai]

Hi,

I am currently looking to convert a transisitor preamplifier circuit operating from a single 12V supply to operate from a 3.3V supply.

The current resistor values for the 12V version are:-

R1 = 20K, R2 = 10K, Transisitor = BC337, RC = 2K7 and RE = 2K. Note: RE has a bypassing resistor of 1uF.

Note: R1 is connected to 12V and together with R2 form a potential divider circuit.

Can anyone help me in changing this circuit so that it can operate from a 3.3V supply?

If you need any further information, please do not hesitate to ask.

Thanks in advance.

 

[audioguru]

Simply calculate the base voltage, emitter voltage and collector voltage when the supply is 3.3V. The emitter voltage will be about 0.5V and the collector voltage will be about 2.6V so the circuit will work. If the value of R2 is increased so that the collector voltage is 1.9V then there will be a little more collector signal swing available.

Without any negative feedback your single transistor will produce about 40% distortion when its output signal level is high.

The emitter bypass capacitor value is so low that frequencies below 240Hz are not amplified much.

Look at my simulation.