The is an iconic component of the golden age of analog radio design. Its dual‑gate architecture and excellent VHF performance made it a favorite for the RF front‑ends of classic amateur radio transceivers and FM tuners. While it has been obsolete for many years, its legacy lives on through the continuing efforts of restorers who maintain and repair the equipment that contains it.

This article serves as an exhaustive resource. We will explore the official specifications, pinout, equivalent parts, application circuits, and the critical differences between the original 3SK41 and modern variants like the 3SK41A and 3SK41B.

The 3SK41 has the following electrical characteristics:

The electrical parameters of the 3SK41 highlight its optimization for low-power, high-gain signal processing. Below is a breakdown of the key data values typically listed in its technical data sheet: Maximum / Standard Value

To help find exact substitute parts or layout diagrams, let me know: What (VHF or UHF) are you targeting? Are you repairing existing gear or building a new circuit ?

The is a high-performance N-channel dual-gate MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) primarily used in radio frequency (RF) applications. While some older records may misidentify it as a relay, it is most recognized in amateur radio and signal processing for its fast switching and low noise characteristics. Key Technical Specifications

V(BR)GSScap V sub open paren cap B cap R close paren cap G cap S cap S end-sub ) : ±7.0V. : 25mA. Maximum Power Dissipation ( PDcap P sub cap D ) : 250mW at ambient temperature ( 25∘C25 raised to the composed with power C Forward Transfer Admittance ( gfsg sub f s end-sub yfsy sub f s end-sub ) : 8.0 mS (millisiemens) minimum. Input Capacitance ( Cisscap C sub i s s end-sub ) : 5.0pF maximum. Pinch-off / Cut-off Voltage ( Vpcap V sub p

Since the 3SK41 has been discontinued for decades, finding original parts can be difficult and expensive. However, the transistor is not unique, and several suitable replacements have been identified by the electronics community. A summary of modern equivalents is detailed in the table below.

RDS(on)cap R sub cap D cap S open paren o n close paren end-sub

A universal replacement part often found in repair catalogs. ⚠️ Usage Considerations

VGS(off)cap V sub cap G cap S open paren o f f close paren end-sub ) : 4.0V maximum. Package Design & Pinout Configuration

, it is known for its ability to handle high-speed switching while maintaining low noise. Jotrin Electronics Key Specifications & Features