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Instrumentation Circuits, Page 1 Testers:
#'sA-BCDEF-GH-KLM-OPQ-RSTUV-Z
Last Updated on:
Monday, October 03, 2011 06:07 PM
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
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.
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.
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.
Links to electronic circuits,
electronic schematics, designs for engineers, hobbyists, students & inventors:
$5 junkbox Circuit Determines Phase Sequence - 04/23/98 EDN-Design
Ideas....Have you ever wondered which way a blower motor is going to turn
when you plug it into anor socket, or have you ever inherited....File
contains multiple circuits scroll to find this circuit.... [Design Idea by
Hugh Adams, Fort Walton Beach, FL]
µC measures High-frequency signals - 03/02/98 EDN-Design
Ideas....To measure a high-frequency signal using an 8-bit µC, the time
period of the measured frequency must be relatively close to the
internal.…File contains many circuits, please scroll to find this one....
[Design Idea by Stan D'Souza, Microchip Technology Inc, Chandler, AZ]
0-50V 2A Bench power supply Circuit - I use the lm10 IC because it
has a reference voltage and that�s useful for dc power supply. With two ICs
can take different output voltage and amperage. This circuit is
protected from short circuit.... [Author: hamed_iranmehr@yahoo.com]
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...Published in Popular Electronics, November 1992 …. [Hobby Corner
Circuit by Dave Johnson]
10 Amp 13.8 Volt Power Supply - Just like other commercial units, this
circuit uses the LM723 IC which gives us excellent voltage regulation. The circuit
uses 3 pass transistors which must be heat sinked….(electronic design added 6/07)
[Radio Amateur Society of Norwich]
12 Volt to 120 Volt Inverter (randy Linscott) - Ever needed a low power
120volt AC power source for your car, van or truck? Well this circuit should do
the trick for you. It will supply 15 watts of AC power to a device. It should power
lamps, shavers, small stereos and small appliances. If you draw to much power ….
[Randy Linscott, designer]
120 VAC 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.... [Designed by David A. Johnson]
12v Battery Capacity Tester - An application for the above mentioned LV
Disconnect circuit that makes testing the amp-hour capacity of batteries a breeze….
[Circuit Design by Burton Lang]
13.8V 20A PSU - This is a Regulated DC power supply with short circuit
protection and with current limiter. (electronic design added 6/07)
