Product Overview
Solid State, Inc. 2N1545A Germanium PNP Power Transistor (NOS)
This vintage power transistor is designed for linear, high-current analog stages where stable gain and predictable thermal behavior matter more than switching speed. Commonly found in classic regulator and amplifier designs, this type of device reflects an era when discrete power control relied on robust metal-can construction and conservative operating margins. A useful synonym in documentation is pass device / series transistor.
Product Condition
Unused, New Old Stock. Preserved from original production-era inventory and not previously installed.
Product Overview
The Solid State, Inc. 2N1545A is a germanium PNP power transistor belonging to the JEDEC 2N1545 family. Devices in this family were widely used in vintage power supplies, audio amplifiers, and industrial control equipment requiring moderate voltage handling with substantial current capability. The TO-3 package supports effective chassis or heatsink mounting in linear power applications.
Key Features
- Germanium PNP power transistor architecture
- Member of the established 2N1545 transistor family
- Rated for moderate voltage and high current operation
- Low-frequency device suited for linear service
- Metal TO-3 package for thermal coupling to heatsinks
- Lower base-emitter voltage than comparable silicon devices
- Historically used in regulated power and audio circuits
Applications
- Repair of vintage linear power supplies
- Restoration of classic audio power amplifiers
- Series pass elements in regulator circuits
- Industrial control equipment maintenance
- Legacy laboratory and instrumentation hardware
- Educational or reference use for germanium power devices
Frequently Asked Questions
What type of transistor is the 2N1545A?
It is a germanium PNP power transistor intended for linear, low-frequency power applications.
Is this suitable for switching power supplies?
No. Devices in the 2N1545 family are designed for linear operation rather than high-frequency switching.
What does the “A” suffix indicate?
The suffix typically denotes a screened or variant device within the same family, though published differences are limited.
Why are germanium transistors still used today?
They are primarily used for restoration or repair of equipment originally designed around germanium characteristics.
You can reinstall this transistor as a series pass element in a vintage linear power supply, mounting it to an existing TO-3 heatsink to restore original circuit behavior.
