• DC CURRENT INDICATOR #4    December 15, 2008
  The circuit below uses some common components to turn on an LED whenever DC current above a certain level is detected.  The circuit uses a very popular LM393 dual voltage comparator from National Semiconductor and a common 1N4148 signal diode.  The diode acts as a crude 0.7v voltage reference.  Only one of the comparators inside the 8 pin package is used.  A pair of resistors across the diode forms a voltage divider, which produce a reference voltage of about 0.015v. ....

Design an Efficient Reset Circuit:  05/01/03 EDN Design Ideas  /  (added 1/05)  When you work with microprocessors, you must ensure that when the power-supply voltage fluctuates to the minimum permissible level, VL, that the processor's ALU continues to operate normally. Also, when you switch on the power supply, the ALU must operate normally when the supply voltage equals or exceeds a certain high level, VH....

Design Low Duty Cycle Timer Circuits:  08/22/02 EDN Design Ideas  /  (added 1/05)  Designing astable circuits using the industry-standard 555 timer is a straightforward process when duty cycles are 50% or greater. However, you must overcome the many pitfalls of low-duty-cycle circuits to arrive at a desired result. Using only ideal components eases the design, but the components themselves are hard to obtain....

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Dual Comparator Thermally Protects Lithium Ion Battery:  09/18/03 EDN Design Ideas  /  (added 1/05)  Most manufacturers recommend that you don't change lithium-ion batteries at temperatures lower than 0°C or higher than 50°C. You can monitor both thresholds by adding a thermistor and dual (window) comparator to a lithium-ion battery charger (Figure 1). Set the low-temperature trip point at 2....

Dual Comparator:  forms temperature-compensated proximity Detector (app note added 5/03)

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Dual Limit Photo-Detector Monitor:  Circuit Ideas for Designers Application Notes Advanced Linear Devices, Inc.  (app note added 6/06)

Dual Limit Window Comparator :  Circuit Ideas for Designers Application Notes Advanced Linear Devices, Inc.  (app note added 6/06)

Dual Micropower Comparator with Integrated 400MV Reference Simplifies Monitor and Control Functions:  DN321  Design Notes (Linear Technology) (app note added 1/06)