What is the Difference Between BJT and FET?
🆚 Go to Comparative Table 🆚Bipolar Junction Transistors (BJTs) and Field Effect Transistors (FETs) are two types of transistors used in electronic applications. The main differences between them are:
- Control Technology: BJTs are current-controlled devices, while FETs are voltage-controlled devices.
- Charge Carriers: In BJTs, the current flows due to both majority and minority charge carriers, while in FETs, the current flows due to majority charge carriers only.
- Terminals: BJTs have three terminals (emitter, base, and collector), while FETs have three terminals (source, gate, and drain).
- Sensitivity: BJTs are more sensitive to changes in the applied voltage, while FETs are less sensitive to variations in the applied voltage.
- Power Consumption: FETs consume less power compared to BJTs.
- Input Impedance: FETs have a higher input impedance compared to BJTs.
- Switching Speed: FETs generally have faster switching speeds than BJTs.
- Noise: BJTs produce more noise than FETs.
- Types: BJTs are of two types, NPN transistors and PNP transistors, while FETs are of two types, N-channel FET and P-channel FET.
- Voltage Drop: BJTs have a higher voltage drop, while FETs have a lower voltage drop.
- Immunity to Radiation: FETs are more immune to radiation than BJTs.
- Thermal Stability: BJTs have lower thermal stability compared to FETs.
In summary, BJTs are current-controlled devices that use both majority and minority charge carriers for current flow and have a higher voltage drop, while FETs are voltage-controlled devices that use majority charge carriers for current flow and have a lower voltage drop. FETs typically consume less power, have higher input impedance, and faster switching speeds compared to BJTs.
Comparative Table: BJT vs FET
The following table highlights the main differences between Bipolar Junction Transistors (BJT) and Field Effect Transistors (FET):
Parameter | BJT | FET |
---|---|---|
Full Form | Bipolar Junction Transistor | Field Effect Transistor |
Control Element | Current-controlled device | Voltage-controlled device |
Types | NPN transistor and PNP transistor | N-channel FET and P-channel FET |
Configuration | Common emitter (CE), common base (CB), and common collector (CC) | Common source (CS), common gate (CG), and common drain (CD) |
Size | Large in size, requiring more space | Smaller in size, taking up less space on a chip |
Input Impedance | Lower input impedance | Higher input impedance |
Output Impedance | Lower output impedance | Higher output impedance |
Current Flow | Due to both electrons and holes (bipolar transistor) | Due to majority charge carriers (unipolar transistor) |
PN Junctions | Has PN junctions (emitter-base junction and collector-base junction) | Does not have PN junctions between source and drain |
Applications | Used as a switch (in saturation and cut-off region) and amplifier (in active region) | Used as a switch (in Ohmic and cut-off region) |
Both BJT and FET are transistors used in various electronic applications, but they have different characteristics and work on different principles.
- MOSFET vs BJT
- BJT vs IGBT
- BJT vs SCR
- IGBT vs MOSFET
- NPN vs PNP Transistor
- Transistor vs Thyristor
- Semiconductor vs Superconductor
- NMOS vs PMOS
- IGBT vs GTO
- IGBT vs Thyristor
- Semiconductor vs Metal
- Bosons vs Fermions
- Fuse vs Circuit Breaker
- Conductor Semiconductor vs Insulator
- Electrical Engineering vs Electronics Engineering
- Resistance vs Capacitance
- Ferromagnetism vs Antiferromagnetism
- EMF vs Voltage
- Magnetic Force vs Electric Force