Viewing posts for the category Sensitive Design

Technology: Low Noise Thermoelectric Cooler (TEC) Controllers

Thermoelectric (Peltier) Coolers

A thermoelectric cooler is a solid-state device made from two alumina ceramic plates with an array of metallized pillars in between.  The pillars are also ceramic--they're made of alternating p-type and n-type bismuth telluride (Bi2Te) semiconductors, alloyed with antimony telluride (p-type) or bismuth selenide (n-type), and connected in series electrically.  The Peltier effect makes them electric-powered solid state heat pumps.   (Thermocouples work the other way round, via the Seebeck effect, but the physics is the same.)

BEOS outtakes: Photographic Film

From the cutting room floor at Building Electro-Optical Systems, Third Edition:

Thermal Runaway Found Useful

This odd circuit  is an on-chip temperature balancer that uses thermal runaway to force N transistor arrays to all run at the same temperature.  BJT dissipation goes up at low temperature, with very high gain.  Here's its step response.