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Current Injector - When you need to measure resistance down to a few micro ohms, this circuit works great. It is powered from two "C" cell batteries and is designed to inject a well regulated one amp of current into the unknown resistance. By measuring the voltage drop across the resistor with a digital voltmeter, the resistance value can be accurately measured. The circuit also is equipped with a low battery monitor. Published in Popular Electronics, November 1992modified on July 11, 2006. . . Circuit by David Johnson P.E.-June, 2000
Current Sense and Bias Voltage Circuits for Avalanche Photodiodes - Linear Technology AN92 __ Designed by Jim WilliamsNov 1st, 2002
Current Source - Getting optimum performance in certain applications requires that some components, sensors, DC motors, transistors, be driven or biased by a constant current. We're mostly familiar with voltage regulators and their ability to maintain a constant voltage under varying current conditions. In this application, your challenge is to provide a constant (spice design) __
Current source allows measuring three-wire RTD - 07/06/00 EDN-Design Ideas In applications in which you need remote measurement of temperature with a three-wire RTD (resistance-temperature detector), it is important to eliminate the ohmic errors caused by the excitation current flowing through the wiring resistance. You can locate the RTD more than 1000 ft from the ADC with wiring resistance in the tens of ohms. __ Circuit Design by John Wynne, Analog Devices, Limerick, Ireland
Current source forms unusually Simple Circuit regulator - 09/12/97 EDN-Design Ideas Simple regulator uses a switching current source to drive a pair of shunt Zener regulators, circuit produces ±15V dual outputs, for total output power of approximately400 mW form100-400-Volt DC source__ Circuit Design by Kennan Herrick, ESI Electronics, San Francisco, CA
Current source has high compliance - 09/01/00 EDN-Design Ideas Current sources are useful in many areas of electronics, such as voltage and current division, current transmitters, excitation of thermistors, RTDs, bridges, potentiometers, and circuit biasing. Current sources are either fixed- or adjustable-current types. For the dual-op-amp current source in Figure 1 , the load current, I L , is adjustable by varying V IN (0 to±1. __ Circuit Design by Frank Vitaljic, Bellingham, WA
Current source has high output impedance - 06/22/00 EDN-Design Ideas A reference current source needs high accuracy, low temperature drift, and high output impedance. Available IC current sources come with some of these features. However, at current levels greater than 1 mA, their output impedance decreases to less than 10 MW. Figure 1 shows a composite 10-mA current-source configuration that has a compliance voltage of 5 to 42V, a set-current error of less than 1%, a temperature drift of less than 45 ppm/°C, and an output impedance of greater than 100 MW. __ Circuit Design by Clayton B Grantham, National Semiconductor, Tucson, AZ
Current Source is Computer Controlled - Often in industrial control systems a constant current source is needed, which is controlled by a computer and referenced to circuit ground. The circuit below converts a zero to 5v signal from a computer’s analog output into a current, with a full scale of 100ma. The circuit shown requires a 9v DC supply . . . Hobby Circuit designed by Dave Johnson P.E.-July, 2008
Current Source Makes Novel Class a Buffer - 3-Apr-08 EDN-Design Ideas A pair of classic current sources in totem-pole configuration enables a novel Class A buffer__ Circuit Design by Horst Koelzow, Winnipeg, MB, Canada
Current Source Mirror - Circuit Ideas for Designers App Note___ Advanced Linear Devices, Inc
Current Source Multiplication - Circuit Ideas for Designers App Note___ Advanced Linear Devices, Inc
Current Source with Gate Control - Circuit Ideas for Designers App Note___ Advanced Linear Devices, Inc
Current sources & mirrors - There are many useful circuit elements: current sources and current mirrors are two of them. Sources and mirrors are so closely related that it is sometimes difficult to differentiate between them. So what?labelling things is a function of language not of electronics! __ Designed by Richard Torrens
Current Sources for Fiber Optic Lasers - Linear Technology AN90 __ Designed by Jim WilliamsApr 1st, 2002
Current Sources for Fiber Optic Lasers - AN90 A large group of fiber optic lasers are powered by DC current. Laser drive is supplied by a current source with modulation added to the signal. The current source, although conceptually simple, constitutes an extraordinarily tricky design problem. There are a number of practical requirements for a fiber optic current source and failure to consider them can cause laser and/or optical component destruction. This App Note describes ten laser current source circuits with a range of capabilities. High and low current types are presented, along with designs___ Linear Technology/Analog Devices
Current sources for fiber-optic lasers: a compendium of pleasant current events - 08/22/02 EDN Technical Article: It takes an aura of thoughtful caution to design a laser current source. A range of circuits that use linear and switched-mode techniques shows how. __ Circuit Design by Jim Williams, EDN's most revered contributor, passed away in June 2011 after a stroke. He was 63.
Current-source is nonvolatile - 02/07/02 EDN-Design Ideas Digitally programmable current sources that feature automatic trimming and retain the setting despite power-down cycles are useful in applications such as RF- and laser-communications drivers. The circuit in Figure 1, for example, i__ Circuit Design by Stephen Woodward, University of North Carolina, Chapel Hill |
