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• CIRCUIT FORMS DIVIDE BY 1.5 COUNTER
  Two inexpensive ICs divide a TTL clock signal by 1.5. By following the circuit with another flip/flop, you could also generate a divide by three function.

• DARKROOM CAMERA SHUTTER TIMER
  This circuit was designed to control a film exposure shutter for a darkroom. It has 8 time steps ranging from 0.35 seconds to 4 seconds. It is activated by a foot switch and draws power from an external 12 volt DC supply.

Electromechanical damping stabilizes analog meter readings:  09/29/05  EDN -- Design Ideas  /  (added 11/05)   Electronics damps meter-needle swings.

Electronic distance meter Based on Motorola 68HC908QY4:  (circuit / schematic design added 6/06)

Eliminate thermoelectric EMF in Low ohm measurements:  06/13/02 EDN Design Ideas  /  (added 1/05)  When two different-metal conductors connect together in a loop and one of the junctions is at a higher temperature than the other, an electrical current flows through the loop. The magnitude of this current depends on the type of metals involved and the temperature differential of the junctions. When you open such a loop, a thermoelectric voltage appears across the open ends....

EMF Field Probe:  (electronic design added 9/02)

Emulator Speeds Testing:  09/25/03 EDN Design Ideas  /  (added 1/05)  Designing and testing embedded hardware can be frustrating if you have to rely on somebody else's perhaps-unready firmware to test your hardware. Often, hardware is ready for testing before debugging and system firm-ware are available from software developers. Microprocessor emulators are solutions but are often expensive, hard to use, and sometimes inappropriate for use by hardware developers,......

Envelope Tracker Quells Jitter:  07/07/94 EDN-Design Ideas  /  (added 6/06) Fig 1's envelope tracking circuit solves the problem of receiving ac-coupled NRZ data over a coaxial data link. Because the spectral content of the NRZ data approaches dc (even with alternate frame inversion), the signal tends to integrate in any ac-coupled stage preceding the zero-crossing detector, despite the low cutoff frequencies. Thus, the dc level of the received data wanders, changing the relative switching point at the comparator.....   

Environmental Compensation on the AD7145:  AN-829 - Analog Devices Application Notes  (app note added 6/06)

E-Power Meter:  Intersil Application Block Diagram  (app note added 6/06)

ERA-SM Test Board: Instructions for Use  AN-60-019:  Application Note - MiniCircuits.com  (app note added 6/06)

ESD Gun Tests IC:  09/12/96 EDN-Design Ideas  /  (added 2/06)   You can use the simple ESD-test gun in Figure 1 to test the effects of ESD through sensitive ICs. A piezo-electric type kitchen gas lighter (the so-called ESD gun) is an excellent fast-static-charge generator. This gun can cause ESD through air and also through conducting and semiconducting materials. These devices also meet home-use safety standards. To build the device, extend the main pin of the gun so that this pin nearly reaches the test pin of the IC. This distance can be as close as 2.5 mm to form a trigger gap. To fire an ESD pulse directed toward the test pin, just squeeze the gun handle, and a fine flash appears at the test pin of the IC. The amount of charge is about 0.2 µC, and the pulse duration varies from 100 nsec to 1 µsec....

ESD Sensitivity Testing of Mini-Circuits ERA-4XSM  AN-60-028:  Application Note - MiniCircuits.com  (app note added 6/06)

ESD Sensitivity Testing of Mini-Circuits ERA-5XSM  AN-60-029:  Application Note - MiniCircuits.com  (app note added 6/06)

ESR Meter:  (diagram added 8/03)

Ethernet 10Base T Simulator Jig yields Zero Emissions:  10/22/98 EDN-Design Ideas  / (added 3/03)   

Expanded Scale Battery Volt Meter:  This circuit is used to measure the voltage on a 12V (nominal) lead acid rechargeable battery system. It was specifically designed for use in solar powered systems, but is general enough that it can be used for automotive or other 12V systems. Lead acid batteries normally spend their working lifetime in the voltage range of 11-15 Volts. This meter circuit was designed to show the voltage range of 10-15V on an analog meter movement, it can be used to show the battery charge state from empty to full. (added 10/05)

Expanded scale indicator revisited:  08/08/02 EDN Design Ideas  /  (added 1/05)  The visualization aid that a previous Design Idea describes allows only the expansion of the upper end of the scale (Reference 1). But what can you do if, according to your project requirements, you need to expand the middle region of the scale? Figure 1a illustrates the challenge. A voltmeter comprises a 100-µA dc meter and a series resistor....