• ACCEPTABLE VOLTAGE INDICTOR
  I have used this circuit many times in custom test fixtures where a simple go-no go indication was needed.  The circuit can also be used to adjust a particular voltage be within specific high or low limits.  The three LEDs will indicate if the voltage is high, low or OK.  When connected to other converters, such as a frequency to voltage converter, a current to voltage converter or a power to voltage meter, it could provide a quick indication of a proper level.

• BROAD BAND 2MHz OPTICAL FIBER RECEIVER
  If you need more sensitivity than the above circuit this circuit provides about ten times more gain. It too is designed around an inexpensive plastic optical fiber detector.

• BROAD BAND 5MHz OPTICAL FIBER RECEIVER
  This circuit is a simple broad band light detector that uses a very inexpensive IC and a PIN photodiode that is packaged for use with plastic optical fibers. It has a bandwidth from 1KHz to over 5MHz. It is great for experimenting with various modulated light sources.

• BROAD BAND 50MHz OPTICAL FIBER RECEIVER VERSION A
  If the above circuit it still too slow, you can try this circuit. What it lacks in sensitivity it makes up for in speed. The circuit attaches a plastic fiber optic PIN photodiode assembly to a small box containing a small 3v battery and a standard BNC plug. When the box is plugged into to the input of an oscilloscope with a 50-ohm termination resistor, it can detect light pulse frequencies beyond 100MHz.

• Brownout Voltage Tester
  I used this circuit years ago to test AC line powered devices under 95vac line voltage conditions.  It has a rating of 250 watts.

A 3-Phase Power Meter Based on the ADE7752:  AN-641 Analog Devices Application Notes  (app note added 6/06)

A 4  to 20 mA loop needs no external power source:  09/13/01 EDN Design Ideas  / (added 11/05)  The simple circuit in Figure 1 uses a low-current-drain MAX407)3H amplifier to sense  current flowing through a 4to 20-mA loop. The circuit senses  current through a 1Ω resistor with a fixed gain of 100 and uses no battery or dc power supply. The low current drain of  amplifier (0.

A Comparison of Leading Switch/Measure Solutions:  Agilent Application Note   (added 6/06)

A Design and Manufacturing Guide for the Lead Frame Chip Scale Package (LFCSP):  AN-772 Analog Devices Application Notes  (app note added 6/06)

A Guide to the Design of Current Feedback Control / AN-4109:  Fairchild Application Notes / (app note added 6/06)

A Low Cost Tamper-Resistant Energy Meter Based on the ADE7761 with Missing Neutral Function:  AN-687 Analog Devices Application Notes  (app note added 6/06)

A Low Cost Watt-Hour Energy Meter Based on the AD7755 (Chinese Version -5/2000):  AN-559 Analog Devices Application Notes  (app note added 6/06)

A Low Cost Watt-Hour Energy Meter Based on the ADE7755 (Russian Version):  AN-559 Analog Devices Application Notes  (app note added 6/06)

A Low Cost Watt-Hour Energy Meter Based on the ADE7755:  AN-559 Analog Devices Application Notes  (app note added 6/06)

A Low Cost Watt-Hour Energy Meter Based on the ADE7757:  AN-679 Analog Devices Application Notes  (app note added 6/06)

A Power Meter Reference Design Based on the ADE7756:  AN-564 Analog Devices Application Notes  (app note added 6/06)

A Precision Wideband Current Probe for LCD Backlight Measurement:  DN101  Design Notes (Linear Technology) (app note added 1/06)

A simple Remote control Tester:  (electronic circuit added 10/05)

A Tamper-Resistant Watt-Hour Energy Meter Based on the AD7751:  AN-574 Analog Devices Application Notes  (app note added 6/06)  With a Current Transformer and a Low Resistant Shunt

A Tamper-Resistant Watt-Hour Energy Meter:  AN-563 Analog Devices Application Notes  (app note added 6/06)  Based on  ADE7751 and Two Current Sensors

AB-2: High Voltage Testing:  A description of high voltage test standards as y relate to Isoloop isolators. These standards include UL1950, UL1577, UL3101-1 and VDE0884. .  (added 6/06)

AB-24: Bench Testing LM3900 and LM359 Input Parameters:  National Semiconductor Application Note   (app note added 2/06)

AC Current Monitor:  Senses high current-flow into power cables.  No wire-cutting, three versions available.  (added 3/05)

AC Line Current Detector:  (electronic schematic / circuit added 4/02)

AC Voltmeters and ammeters:  Electronic circuit design (added 02/05)

Acceleration Monitor using ADXL202 and AVR:  (circuit / schematic design added 6/06)

Accurate Digital LC Meter:  Based on PIC16F84A microcontroller, 16x1 LCD and LM311 IC (circuit added 8/06)

Accurately measure resistance with less than perfect components:  11/11/04 EDN Design Ideas  / (added 5/05)  For transducers, such as strain gauges or rmistors, you must accurately and inexpensively measure resistance using circuitry built with imperfect components and in which gain and offset errors can significantly limit  accuracy of ohmic measurements. The right circuit topology makes it possible to eliminate most error terms while measuring ohms, leaving  accuracy to be determined by jus...

AC-power monitor uses remote sensing:  04/26/01 EDN-Design Ideas  / (added 6/06)   

AD7751 Reference Board Design in Gerber Format:  AD7751 Analog Devices Application Notes  (app note added 6/06)

AD9850 DDS daughterboard:  (schematic / circuit added 05/07)