2N4861 JFET — Specifications & Equivalents
Manufacturer: Multi-source (JEDEC registered part number)
About the 2N4861
The 2N4861 is an N-channel JFET with a drain–source voltage (VDS) rating of 30 V, a continuous drain current (ID) of 0.008 A and an on-resistance (RDS(on)) of 60 Ω. It can dissipate up to 0.36 W and is rated to a junction temperature of 175 °C. It is available in TO-18 and TO-206AA packages, so confirm the pinout of the exact variant you order.
At a glance
- Type: N-channel JFET
- Max drain–source voltage (VDS): 30 V
- Max continuous drain current (ID): 0.008 A
- On-resistance (RDS(on)): 60 Ω
- Power dissipation (PD): 0.36 W
- Max junction temperature (TJ): 175 °C
- Package: TO-18, TO-206AA
- Manufacturer: Multi-source (JEDEC registered part number)
Typical applications
With its 30 V drain–source rating the 2N4861 sits in the low-voltage class of switching MOSFETs, typically found in 12 V and 24 V automotive and industrial rails, synchronous buck converters, load switching and reverse-polarity protection and H-bridges for small motors.
At 0.008 A it is aimed at small-signal and light-load switching rather than power conversion.
On-resistance of 60 Ω is relatively high, so this part is better suited to low duty-cycle or low-current switching than to continuous high-current conduction.
Choosing a replacement for the 2N4861
A drop-in substitute for the 2N4861 must be the same N-channel type and offer a drain–source rating of at least 30 V, a continuous drain current rating of at least 0.008 A and an on-resistance no higher than 60 Ω if efficiency and heat matter.
Mechanically, check the replacement against the TO-18 and TO-206AA footprint and confirm the pin order — parts sharing a package outline do not always share a pinout.
Because 2N4861 is a JEDEC-registered part number rather than one vendor's proprietary series, it is produced by several manufacturers. Datasheet figures vary slightly between them, so check the datasheet of the brand you actually buy — this also makes like-for-like sourcing easier.
Where the application switches inductive loads or runs near the voltage limit, keep extra headroom rather than choosing a part that only just meets the original numbers.
Frequently asked questions
What is the 2N4861?
The 2N4861 is an N-channel junction field-effect transistor (JFET). It is rated for 30 V drain-source and 0.008 A continuous drain current.
What is the maximum voltage of the 2N4861?
The 2N4861 has a maximum drain-source voltage (Vds) of 30 V. Treat this as an absolute maximum and design with margin, especially when switching inductive loads.
How much current can the 2N4861 handle?
It is rated for 0.008 A of continuous drain current, with power dissipation limited to 0.36 W. Real-world capability depends on your heatsinking and ambient temperature.
What is the on-resistance of the 2N4861?
On-resistance (Rds(on)) is 60 Ω. Multiply by the square of your load current to estimate conduction loss.
What package does the 2N4861 come in?
It is listed in TO-18 and TO-206AA. Verify the pinout of the specific variant, as one outline can carry different pin assignments.
What can I use to replace the 2N4861?
No verified equivalents are listed yet. Choose a part of the same polarity that meets or exceeds every rating above and shares a compatible package and pinout.
Key Specifications
| Type | JFET |
|---|---|
| Channel Type | N -Channel |
| Drain-Source Voltage (Vds) | 30 V |
| Gate-Source Voltage (Vgs) | 4 V |
| Drain Current (Id) | 0.008 A |
| Drain-Source On-Resistance (Rds) | 60 |
| Rise Time (tr) | 10 nS |
| Junction Temperature (Tj) | 175 °C |
| Package | TO-18 TO-206AA |
| Power Dissipation (Pd) | 0.36 W |
Equivalent & Replacement Parts
No verified equivalents are listed for 2N4861 yet.