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Tester or
Instrumentation
Circuits, Page 1e
Testers:
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Last Updated on:
Wednesday, November 29, 2017 05:38 AM |
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Circuits Designed by Dave Johnson, P.E. : |
- 1 AMP
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 1992
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- 120vac
Under Voltage Tester
Using a cheap 24vac transformer, this circuit can test a product under low 95vac
conditions. With the components show, it has a rating of 250 watts max.
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- 20MHz VCSEL
3mW LASER TEST CIRCUIT
This circuit takes advantage of some new vertical cavity surface emitting lasers (VCSEL)
that don’t require light output control circuits. The circuit shows how to drive the
device from a single high speed CMOS IC. The circuit can easily be modified to
transmit signals from kilohertz to about 50MHz.
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- 40KHZ LED
TEST SIGNAL GENERATOR
This 40KHz crystal controlled oscillator circuit drives an infrared LED with
powerful 40ma pulses. The circuit can be used to test optical communications
circuits, designed to receive 40KHz modulated light signals.
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Links to electronic circuits,
electronic schematics, designs for engineers, hobbyists, students & inventors:
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8 Hints for Better RF Signal Generator Measurements - Aligent Application
Note (app note added 04/05/06) |
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8 Hints for Making Better Spectrum Analyzer Measurements - Aligent App Note
(app note added 6/07) |
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8 Stage LED VU Meter - The circuit below uses two quad voltage comparators
(LM339) to illuminate a series of 8 LEDs indicating volume level. Each of the 8
comparators is biased at increasing voltages set by the voltage divider so that the
lower right LED comes on first when the input is about 400 millivolts or about 22
milliwatts peak in an 8 ohm system. The divider voltages are set so that each
LED....(circuit / schematic design added 6/06) |
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80 Meter CW ARDF Receiver - (circuit / schematic design added 6/06)
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80 Meter DSB Transmitter - amateur radio construction projects…. [from Peter
Parker's website] |
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8038 Function Generator - Produces sine, square and triangle waves from 20Hz
to 200kH. Harris Semiconductors. [Written by Bill O'Neil] |
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8038 Function Generator - Built around a single 8038 waveform generator IC,
this circuit produces sine, square or triangle waves from 20Hz to 200kHz in four
switched ranges. There are both high and low level outputs which may be adjusted with
the level control. This project makesa useful addition to any hobbyists
workbench as well.... [Andy Collison, designer] |
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8038 Generator - ICL8038 signal generator chip, manufactured by Intersil. An
improved version, made by Exar corp. is available (XR8038A). It can be used to produce
three types of waveforms, sine, square and triangle. The frequency, amplitude and duty
cycle can be varied, and selection of waveform is done digitally. To further reduce
the complexity, a 3-to-1 switch may be used in place of the digital selection
circuitry. I made use of the digital selection mechanism because switches available on
the market are prone to dirt accumulation and poor contact quality. Besides, the
digital method is a lot cooler! ….(electronic schematic added 11/08) |
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89C2051 PROTO BOARD - This single sided proto board provides an
economical solution for developing and testing the projects around Atmel 20 pin series
u-controllers (89Cx051 & AVR)…. [M Asim Khan, asimkhan@sat.net.pk] |
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9435 PCI Performance Measurements-Concepts & Practical Application - Agilent
Application Note....[App Note] |
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