Product Overview
TO-3 Silicone Thermal Insulator Pads – Unused, New Old Stock
These silicone thermal insulator pads are designed for mounting TO-3 package power transistors to a grounded heatsink while maintaining electrical isolation. Used between the transistor case and aluminum / steel heat spreader, they provide consistent thermal transfer without liquid compounds. For best results, ensure clean, burr-free surfaces before installation.
Product Condition
Unused, New Old Stock. Supplied as 10 pieces per sheet in bulk packaging.
Product Overview
TO-3 metal-can transistors such as the 2N3055 and MJ15003 require electrical isolation from the heatsink because the case is commonly connected to the collector. These silicone pads provide a dry, conformable interface that transfers heat while preventing electrical contact between the device case and chassis. Unlike mica washers that require grease, silicone pads install cleanly and maintain long-term stability. The flexible construction helps accommodate minor surface irregularities in typical amplifier and power supply builds.
Key Features
- Precision cut for TO-3 package footprint
- Provides electrical isolation between transistor case and heatsink
- Dry installation – no thermal grease required
- Conformable silicone construction
- Suitable for high-power transistor mounting
- 10 pads per sheet
- Bulk packed for bench or production use
Applications
- Audio amplifier transistor mounting
- Linear power supply assemblies
- Industrial control chassis builds
- Bench repair of vintage equipment
- Prototype power electronics projects
- Replacement for mica insulators in TO-3 hardware
Frequently Asked Questions
Are these compatible with all TO-3 transistors?
They are sized for the standard TO-3 metal-can footprint commonly used by power transistors such as the 2N3055 and similar devices.
Is thermal grease required?
No. These silicone pads are designed for dry installation and do not require grease for typical applications.
Do these provide electrical isolation?
Yes. They electrically isolate the transistor case from the heatsink while allowing thermal transfer.
How are they supplied?
Each listing includes one sheet containing 10 TO-3 silicone insulator pads.
Use them for audio amplifier transistor mounting with dry installation – no thermal grease required, positioning each pad between the TO-3 case and heatsink before securing it to your chassis.
