2SK170-GR Silicon N-Channel Unipolar Junction FET

A 2SK170-GR is a 3 pin silicon N-Channel unipolar junction type field effect transistor which is used for various applications in different circuits and used commonly in low noise audio amplifiers. 


2SK170-GR Pins Assignment:

2SK170-GR JFET has three pins. Below in Figure  pins assignment for transistor 2SK170-GR is shown. At position 1 is Drain right after that at position 2 is Gate and finally at position 3 is Source.

2SK170-GR Pins Description:

Pin Number

Pin Name

Description

1

Drain

Current flow in through this, connected to positive supply

2

Gate

Current flow out through gate normally connected to ground.

3

Source

Connected to ground

Features of 2SK170-GR:

  • N-channel JFET for low noise audio applications.
  • High input impedance.
  • High breakdown voltage.
  • Suitable for first stages of EQ and M.C. head amplifiers.
  • Gate-drain voltage: -40 V (at TA = 25 C)
  • Gate current: 10 mA (at TA = 25 C)
  • Drain power dissipation: 400 mW (at TA = 25 C)
  • Junction temperature: 125 C
  • Gate cut-off current: -1 nA (VGS = −30 V, VDS = 0)
  • Gate-drain breakdown voltage: -40 V  (VDS = 0, IG =-100 uA)
  • Package: TO-92

Note:

  • TA: Ambient Temperature
  • VGS: Gate to source voltages
  • VDS: Drain to source voltages
  • IG: Gate current

Equivalent of 2SK170-GR: The equivalent of 2SK170-GR is LSK170.

Uses of 2SK170-GR:

The Junction Filed Effect Transistors (JFET) designed in different packages. 2SK170-GR is designed in TO-92 package which construction is now obsolete and not suggested for new designs because of its non-availability in the market. They are still count for different uses and are most likely used for low noise audio amplifier applications other than that it can also be used in design of headphones. The reliability may decrease due to continuous use of this transistor under heavy load even if it used between designed parameters. 

Working of 2SK170-GR:

As discussed above, 2SK170-GR is a unipolar N-Channel junction field effect transistor which is used for various applications including low noise amplifiers. In order to understand its working it would impossible without knowing about its pins and their role in the circuit.

2SK170-GR is a unipolar N-channel JFET which is voltage controlled three terminal device and is the major reason of difference from bipolar junction transistor (BJT) which is current controlled three terminal device.

The three terminal of 2SK170-GR N-channel JFET are drain, gate and source. Whenever JFET turns ON the flow of current will be due to electrons because of N-channel JFET. The Drain terminal is connected with load and positive terminal while Source is connected with ground in the circuit. Meanwhile, Gate is fed with zero or negative voltage depending upon the requirement of the circuit. To turn ON N-channel JFET, positive voltages are applied to drain and zero voltage is applied to Gate this will allow the flow of current between drain and source. On the other hand, to turn it OFF either cut-off voltages applied at drain or apply negative voltages at gate this will reduce the current flow between drain and source further increase in negative voltages at gate will completely turn OFF the transistor.

2D Model of 2SK170-GR:   

Below in figure is the 2D model for 2SK170-GR. All values are in millimeters.