PN Control Field Transistors (JFETs)

Field-effect transistors with a control PN junction are JFET components in which the gate forms a p-n junction with the channel and controls the drain-source current due to the applied voltage. They are bought when you need high input resistance and careful operation with low-signal circuits, for example, in the input stages of amplifiers and noise-sensitive nodes.

Basic characteristics of field-effect transistors with a control PN junction

The catalog contains N- and P-channel components. They differ in the control polarity (VGS sign) and the direction of conduction, so the choice depends on the power supply circuit and the required polarity of the control voltage.

When ordering products, you need to pay attention:

• on VDS(max). The maximum allowable drain-source voltage.
• ID(max). The maximum drain current that the transistor can withstand under specified conditions.
• IDSS. Conventionally, the maximum current for a given JFET is at zero gate offset.
• VGS(off)/Vp (cut-off voltage). The VGS value at which the channel "closes" (the drain current tends to zero).
• VGS(max). The maximum allowable gate-source voltage.

Advantages of field-effect transistors with a control PN junction

JFET is appreciated for its high input impedance: the electronic component almost does not load the signal source and is suitable for input stages. Additionally, such devices are often ordered in cases where low noise and good linearity in analog nodes are important.

How to choose a field effect transistor with a control PN junction

Depending on the specifics of the application, when choosing a JFET, they look at different key parameters. In amplifiers and input stages, high input impedance and low gate current are important, as well as noise/linear properties and the convenience of setting the operating point via IDSS and VGS(off). In switches (analog switches, attenuators), the channel resistance in the open state of RDS(on), the VGS range (off) and leakage currents/IDSS come to the fore.

Errors when using field effect transistors with a control PN junction

Many users forget that to close, you need the opposite sign of VGSV_{GS}VGS (usually negative for the N channel). Because of this, they set the control polarity incorrectly or get a mode where the transistor is constantly open. The second typical error is an overload of the gate: an attempt to apply too much VGSV_{GS}VGS or to allow a direct offset of the p-n junction of the gate in the signal circuits increases currents, distorts the signal and can damage the device.

A large selection of transistors with a control PN junction with delivery across the Russian Federation

Choose a suitable JFET for the price and functionality and make a purchase in the CHIP and DIP online store. Add devices and the necessary strapping (resistors, connectors, boards/accessories) to the shopping cart - this way it is more convenient to close the project with one order. One-time and wholesale purchases with delivery in Moscow and throughout Russia are available.

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Products from the group «PN Control Field Transistors (JFETs)» you can buy wholesale and retail.