If you are designing a PCB or Perf board with this component then the following picture from the MPF102 Datasheet will be useful to know its package type and dimensions. When it is biased using -7.5V on the gate pin, the JFET blocks the flow of current between the Drain and Source pin and thus turns off the LED. When the gate pin is grounded, the JFET allows current to flow from drain to source and thus the LED is turned on. The above two images should how a load (LED) can be toggled using a JFET like MPF102. In order to top the JEFT from conducting a negative gate voltage has to be applied to the gate pin, for the MPF102 it should be typically -7.5V. If you cannot find the supplier, then consider upgrading to NTE457 which his slightly pricy but availability will not be a problem.Ī JEFT is considered to be in on state by default that is even if the gate single is not provided (0V) the JFET will allow current to flow from Drain to Source. The schematic symbol and physical diagram of a P-channel JFET. Generally, N-channel JFETs are more commonly used than P-channel (Figure 2). The next section will go over P-type channel JFETs, which are also manufactured. Provided you have the right FET, it can be used in pre-amp circuit to achieve gain of +12dB or high. Example schematic symbol and diagram of an N-channel JFET. Hence be careful which employing one in your designs. The clone FETs available in the market does not seem to follow the datasheet strictly. The closest equivalent for NTE457 is the J113 FET. The JFET is currently no longer in production but till the demand for it has created many clones in the market. The MPF102 is a JFET that has been used in many amplification circuits because of its low price. Note: Complete Technical Details can be found at the MPF102 datasheet given at the end of this page. General Purpose N-Channel Junction Field Effect Transistor.So they are not recommended for new designs.Ĭurrent flows out through Drain, normally connected to ground. The JFET is no longer in production and finding it might be difficult. The MPF102 JFET is a popular N-Channel JFET that is commonly used in low power amplifier circuits.
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