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Tester or
Instrumentation
Circuits, Page 8
Testers:
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Last Updated on:
Monday, October 03, 2011 06:08 PM |
| Circuits
Designed by Dave Johnson, P.E. : |
- LASER/LED
LIGHT OUTPUT INTENSITY METER
This circuit uses a large 1cm X 1cm silicon PIN photo diode and a transimpedance
amplifier to measure the light power output of infrared and visible LEDs and laser
diodes. It can be modified to produce almost any milliwatts to volts scale factor.
It can be connected to either a multi-meter or an oscilloscope.
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Light Monitor 2
The circuit below takes advantage of a low power op amp with a “rail to rail”
feature. The single resistor R1 defines the light sensitivity of the circuit.
The output voltage is directly proportional to the intensity of light striking the
small photodiode D1. In total darkness, the output voltage will hover near
zero volts. The capacitor C1 is chosen to filter our most AC components of the
light but by decreasing its value to just a few picofarads, the circuit can operate
in the tens of kilohertz range. A faster op amp will be needed for higher
speed signals.
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- LIGHT
RECEIVER WORKS FROM 1KHz TO OVER 70MHz
This circuit uses one tiny C-MOS inverter IC to form a modulated light receiver with
a very fast response. It is designed around a PIN photo diode that is packaged for
use with plastic optical fibers. It can be used as an optical fiber receiver. By
using the open end of the optical fiber it can "sniff" out any modulated light
signals.
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Low Value Capacitance Meter
This circuit was originally designed to measure the volume of fluid inside a medical
syringe. As designed, it produces a zero to 5 volt output, corresponding
to a capacitance change of about 10 picofarads. With a digital voltmeter, at
its output, it can resolve a capacitance change of 0.002 picofarads or 2
femtofarads. (added 12/04)
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Links to electronic circuits,
electronic schematics, designs for engineers, hobbyists, students & inventors:
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Laser/Led Light Output Intensity Meter - This circuit uses a large
1cm X 1cm silicon PIN photo diode and a transimpedance amplifier to measure
the light power output of infrared and visible LEDs and laser diodes. It can
be modified to produce almost any milliwatts to volts scale factor. It can
be connected to either a multi-meter or an oscilloscope. …. [Designed by
David A. Johnson] |
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Latching Continuity Tester - A continuity tester is a must on
every service bench for testing cables, pcboards, switches, motors, plugs,
jacks, relays, and many other kinds of components. But there are times when
a simple continuity test (Tony van Roon's or your multi-meter) doesn't tell
the whole story. For example, vibration-induced problems in automobile
wiring can be extremely difficult to.... [Tony van Roon's circuit] |
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Latching Continuity Tester 1 - This Latching Continuity Tester can
help you locate those difficult-to-find intermittent short and opens that
other testers always seem to miss. It has been part of my workbench for
many.... |
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LB-25: Linear Brief 25 True RMS Detector - National Semiconductor
Application Note (app note added 2/06) |
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LB-48: Linear Brief 48 Simple Voltmeter Monitors TTL Supplies - National
Semiconductor Application Note (app note added 2/06) |
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LC- & Q-meters-Radiometer MM1f multimeter - Modification in particular to
achieve better reading between 20nH-2µH coil inductance. Note the series coil, it is
the secret why it is possible to measure inductance values down towards zero. (Since
it is a gif file it prints better than it seems on the screen). It is usually no
problem....(added 07/07/07) [Jan-Martin Nøding's site] |
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LC Meter Based on the AVR MicroController - Calculates and displays L and C
from oscillation frequency using reference components. This instrument requires
two precision components: A precision capacitor and a precision inductor. You only
need to start with one precision component, either the reference capacitor or the
reference inductor, and using this meter, you can select or adjust the other precision
component. In my case, I used a pretty high accuracy BK Precision
inductance/capacitance meter and sorted through piles of inductors and capacitors to
find those that had the lowest error. I then used those parts,….... |
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LCD Frequency Counter PIC16F84 - .... |
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LCD Panel Meter How to make a volt and amp meter for your battery bank.Click Here
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LED Ammeter - Measures current up to 10A with selected 100mA, 10mA and 1mA
resolutions. (circuit added 8/06) |
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LED Audio UV Monitor - The circuit is completely conventional, and is based
on the application notes from National Semiconductor. The circuit is shown in Figure 1
and as you can see it uses a single IC and a few discrete components. The extra diode
(D3) is included to ensure that the DC to the LEDs is almost unfiltered....(added
5/02) |
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LED Battery Condition Indicator - In the circuit below, a quad voltage
comparator (LM339) is used as a simple bar graph meter to indicate the charge
condition of a 12 volt, lead acid battery. A 5 volt reference voltage is connected to
each of the (+) inputs of the four comparators and the (-) inputs are connected to
successive points along a voltage divider. The LEDs.... [Bill Bowden's circuit] |
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