2N5457 is a small JFET (Junction Field Effect Transistor) transistor. It’s datasheet mentioned that it is most suitable for audio related switching applications. It comes in a three pin TO-92 through hole package. You can see the physical appearance, pinout and the symbol of the 2N5457 JFET in below given image.
Let’s find out what are the key features of 2N5457 JFET transistor.
- High gain N-Channel type
- Drain and source pins are interchangeable.
- High impedance for AC input circuits
- High resistance for DC input circuits
- Low input capacitance and transfer capacitance
- Low intermodular distortion and cross modulation
- Maximum of 25V drain to source voltage
As mentioned above 2N5457 is suitable and recommended for audio related switching applications. Such as small amplifiers like guitar preamplifiers, podium microphone preamplifiers, condenser microphone preamplifiers etc. So let’s find out how to build a simple small guitar pre amplifier using 2N5457 JFET. Such preamplifier circuit is given in below image.
As you can see it only requires very small number of components. 2N5457 JFET transistor does the main task of amplifying the input signal from the guitar pickup. Guitar pickups are electro magnetic devices that outputs a signal in mV range when the strings are moved. This preamp amplifies that mV range signal to a somewhat high amplitude signal so when a power amplifier amplifies it the signal has less noise and distortions. There are two capacitors are used in power rail and in series with the output signal the purpose of these capacitors are to filter out any DC component from the circuit and to bypass the small background noises occurred due to ambient electromagnetic interferences to the guitar pickup. Considering the small amount of components required and lack of difficulty this would be a ideal circuit for a beginner in electronics and for a guitar lover as well.
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