Capacitor ESR or Electrical Series Resistance is the sum of all in-phase AC resistance of a capacitor. This includes the resistance of the plate, dielectric, electrolyte solution and even the resistance of the terminal leads at one particular frequency. It is electrically equivalent to a resistor connected in series with the capacitor as the name implies. A perfect capacitor will have a zero in-phase resistance or zero ESR. ESR is an indication of the capacitor’s build quality, the lower the ESR the higher the quality.

Motherboards and power supplies utilizing high frequency AC use LOW ESR capacitors to prevent high power dissipation. The classic power dissipation formula “I squared times R” will show you that your capacitor will generate more heat if you increase its resistance (ESR). Low quality capacitors employed in high frequency applications
will often have high ESR causing too much heat build up and would eventually cause the capacitor to bulge and self-destruct. This is the classic example of bulging capacitors on a motherboard as seen on this picture.

Best in Technology 1st place
accelerometer sensor array column for slope stability monitoring
UPD
by:
Rudolf Dumo,Earl Anthony Mendoza,Wilfredo Sepulchre
advisers:
Marc Talampas, MSEE,Michael Lochinvar Abundo, MSEE

Best in Technology Runner-Up
Sugpo: Mobile Robot Platform
UPD
Lawrence Y. Lee,Oliver John N. Tizon
adviser:
Engr. Menandro D. Roxas

Best in Technology Honorable Mention
PDA Mobot
Adamson University
Arian Hero Napa,Eugenio Piñon,Marion Anthony Bugnot,
Jay Christian Merle, Reymond Cielo
adviser:
Engr. Alain Bernard Rañola

Most Commercializable 1st Place
Axel Activity Monitor
UPD
Raissa Aranas,Virna Mae Dizon,Stephen Alfred Quedi
advisers:
Engr. Michael Lochinvar Abundo, MS EE,Engr. Marc Caesar Talampas, MS EE

Most Commercializable Runner-Up
TexTag : RFID Tracking System for TB Kits
UPD/Ateneo
Rosanno JC de Dios,Earl Anthony Mendoza
& Joshoua C. Esmenda, Mark Andrew S. Mateo
advisers:
Michael Lochinvar Abundo, MSEE, Joel Joseph Marciano Jr PhD
& Dr. Nathaniel Libatique

Most Promising Team 1st Place
FLASH FLOOD EARLY WARNING DEVICE
Mindanao State University – General Santos City
Lovely Joy C. Decatoria, Ivy R. Entea, Jay Paulo E. Macoy
adviser:
ENGR. DIOGENES ARMANDO PASCUA

Most Promising Team Runner-Up
Microcontroller-based Proportional-Integral-Differential (PID)
Notre Dame of Dadiangas University
Mark Timothy B. Honor
adviser:
Engr. Franz Duran

Source: http://tech.groups.yahoo.com/group/microdesigncontest/message/2166

The standard smoke detector costing about 300 pesos on your local hardware is the ionization type smoke detector. It is the cheapest type of home smoke detector utilizing the radioactive Americium-241 to detect the presence of smoke. Americium emits alpha particles which makes the air inside the smoke detector unit partially conductive.  Smoke particles absorb alpha particles and increases the
resistance of the air inside the smoke detector. The rise in the
electrical resistance of the air is detected by the ASIC and then it triggers a piezoelectric horn.

Ionization type smoke detectors are cheap and accurate but you may be concerned about AM-241 which actually emits
radioactive particles inside your home. FDA says that the
alpha particles emitted by the standard smoke detector is lesser than the amount you are going to get from sun exposure.

On the other hand, photoelectric
smoke detectors use an LED and a photodetector combination. The photodetector senses the presense of light that is reflected by the smoke particles and triggers an alarm unit. Early photoelectric smoke detectors are prone to false
alarms because of dust build up. Newer ASICs from TI, Allegro and other manufacturers  resulted in a more accurate and cheaper photoelectric smoke detectors.

It is important to note that ionization and photelectric detectors detect different types of smoke. Ionization type is more sensitive on smoke particles with small sizes that usually comes from high temperature fires while the photoelectric type is sensitive to large sized smoke particles coming from slow, smouldering fires.