Product Overview
Motorola MCR406-3 Silicon SCR Thyristor (Unused NOS) with Mica Insulator
This Motorola MCR406-3 is a silicon controlled rectifier (SCR) thyristor designed for general-purpose line-voltage control applications.
Part of Motorola’s long-running plastic thyristor families, the MCR406 series was engineered for reliable switching and phase-control duties in consumer and industrial electrical equipment.
Product Condition
This unit is unused, new old stock. It includes the original mica insulating disk. The device has been kept in original packaging or controlled storage and shows no signs of prior installation or electrical use.
Product Overview
The MCR406-3 is a unidirectional silicon controlled rectifier intended for AC line-powered control circuits where dependable triggering and current handling are required. Unlike a triac, this SCR conducts in a single direction once gated, making it suitable for rectified or controlled conduction designs.
Motorola SCRs from this era earned a strong reputation for durability and predictable behavior in real-world mains environments, particularly in appliances and control assemblies that demanded long service life.
Key Features
- Silicon controlled rectifier (SCR), unidirectional thyristor
- Motorola MCR406-3 part number for exact replacement matching
- Plastic-packaged power thyristor with axial-style leads
- Designed for line-voltage AC control applications
- Member of the MCR406-1 through MCR406-4 device family
- Standard-sensitivity gate suitable for power control circuits
- Supplied with mica disk for electrical isolation to heatsink
- Well-suited for phase-angle and on/off control designs
Applications
- Heater and temperature control circuits
- Light dimmer and lighting control assemblies
- AC motor speed control systems
- Static switching in line-powered equipment
- Legacy appliance and industrial control repairs
- Educational and experimental power electronics projects
Frequently Asked Questions
Is this device a triac?
No. The MCR406-3 is a silicon controlled rectifier (SCR), which conducts in one direction only once triggered.
What does the “-3” suffix indicate?
The suffix identifies the voltage class within the MCR406 family. Exact voltage ratings should be verified against the original Motorola datasheet.
Does this include mounting hardware?
A mica insulating disk is included. Additional mounting hardware or heatsinks are not supplied.
Is this suitable for modern new designs?
It is best suited for replacement or restoration of existing designs originally specified for the MCR406-3. New designs typically use currently produced equivalents.
Can this be used on 120V or 240V AC systems?
The MCR406 family was designed for line-voltage applications, but exact suitability depends on the specific circuit and verified datasheet ratings.
Built for an era when components were designed to endure, this Motorola SCR has waited patiently on the shelf. Where it conducts next is entirely up to the circuit you put it in.
