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Saturday, February 14, 2015

Insulation Resistance Testing - AEMC

This Insulation Testing Reference by AEMC Instruments is a Must Read for all Instrumentation and Electrical Professionals. Even Students and Enthusiasts who want to learn more about Insulation, can find this informative. The other reference articles also are of Learning Interest. Insulation Testing is a Part of Power, Energy, Green, Solar Systems as well. It is an Important part of Product Safety.

Megohmmeters/Insulation - AMEC

Read - Understanding Insulation Resistance Testing
AEMC is an industry leader in current measurement probes, power quality analyzers, ground resistance testers and insulation resistance testers. It was Founded in 1893.

Understanding Insulation Resistance Testing - AMEC

AEMC Instruments - 200 Foxborough Blvd., Foxborough, MA 02035 USA

Seen above is the Megohmmeter from AEMC. 6505 is a portable battery/mains powered instrument in a rugged field case.

This Features include automatic calculation and presentation of the Dielectric Absorption Ratio (DAR) and Polarization Index (PI). The Model 6505 displays the test voltage, insulation resistance and the leakage current during the test.

Friday, February 06, 2015

Quad-Differential-Comparator-LM339-TI

These devices consist of four independent voltage comparators that are designed to operate from a single power supply over a wide range of voltages. Operation from dual supplies also is possible, as long as the difference between the two supplies is 2 V to 36 V, and VCC is at least 1.5 V more positive than the input common-mode voltage.

Quad General Purpose Differential Comparator - LM339

An application from an old TI datasheet showing the versatility of this comparator. For me it was a workhorse and like LM324 was used in many products.

Quad General Purpose Differential Comparator - LM339 
Current drain is independent of the supply voltage. The outputs can be connected to other open-collector outputs to achieve wired-AND relationships.

Differential to TTL convertor using LM339
  • Single Supply or Dual Supplies
  • Wide Range of Supply Voltage:
  • Low Supply-Current Drain Independent of Supply Voltage... 0.8 mA Typ
  • Low Input Bias Current ...25 nA Typ
  • Low Input Offset Voltage . . . 2 mV Typ
  • Common-Mode Input Voltage Range Includes Ground
  • Differential Input Voltage Range Equal to Maximum-Rated Supply Voltage . . . ±36 V
  • Low Output Saturation Voltage
  • Output Compatible With TTL, MOS, and CMOS

Extra Extra !