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Tester or Instrumentation Circuits, Page 9
Testers:  #'s    A-B    C    D    E    F-G    H-K    L    M-O    P    Q-R    S    T     U    V-Z
Last Updated on: Friday, March 12, 2010 12:07 PM


Circuits Designed by Dave Johnson, P.E. :
  • MODULATED LASER DIODE TESTER
    This circuit can either be used to test laser diodes or as a general purpose modulated light source. The circuit has an adjustable diode threshold current and an adjustable modulation frequency. The frequency can be adjusted from below 30KHz to above 50MHz. It is powered from a 9v battery.
  • NPN/PNP TRANSISTOR TESTER
    I designed this circuit about 30 years ago and still use it from time to time. It is powered from a 3v battery. It makes a tone when the transistor tests good. It can be used to determine device type (NPN or PNP) and the base, collector or emitter transistor pins. It can also test most transistors will still connected to a circuit.

Links to electronic circuits, electronic schematics, designs for engineers, hobbyists, students & inventors:
 

Machine Vibration Activates Hour Meter - 01/16/97 EDN-Design Ideas:  by David Johnson Battery-powered digital hour meters commonly monitor how long a machine is in operation by detecting when the machine is supplied with power. However, it is often difficult or dangerous to connect a battery-powered hour meter to a line-powered machine. When the machine being monitored....(added 09/05)
Magnetic field probe requires few components - 12/15/06 EDN-Design Ideas:  (design idea added 05/06/07)   Hall-effect sensor and DMM explore stray fields.
Magnetometer - (schematic added 8/03)
Mains Voltage Indicator - The solidstate voltmeter circuit described here indicates the mains voltage with a resolution that is comparable to that of a general-purpose analogue voltmeter. The status of the mains voltage is available in the form of an LED bar graph.....(electronic Circuit / Schematic added 10/04)
Make a Low Cost Benchtop Power Meter - 09/11/98 EDN-Design Ideas:  (design idea added 6/06)
Make Your Own Shunts - Using a modern multimeter to measure current can sometimes be difficult.  Many of these meters will only measure up to one amp.  However, may 112-volt DC powered projects draw a lot more than that. If you have ever thought of purchasing a commercial shunt to solve the problem, your know just how expensive they can be.... (Tony van Roon's electronic design added 2/06)
Making Differential Probes - For sensing audio signal voltages across devices that are not ground referenced (added 6/03)
MAR/RAM Test Fixture Instructions - Application Note MiniCircuits.com  AN-60-018 (app note added 04/05/06)
M-Audio Recorder Use - It easily outperforms my soundcard! But there is a problem (as usual). The device emits a huge amount of hum and buzz and a receiver can't be anywhere near it. A lot of it sounds just like 60 Hz line noise, too, making it more confusing. I came up with a solution that completely eliminates the interference... (electronic design added (6/07)
MAV Test Fixture Instructions - Application Note MiniCircuits.com  (app note added 04/05/06)
MAX6953 Development board - ….(electronic schematic added 08/08)
Measure humidity and temperature on one TTL line - 08/30/01 EDN-Design Ideas:  By combining the responses of an Analog Devices (www.analog.com)AD590 temperature sensor and a Humirel (www.humirel.com)HS1101 humidity sensor, you can generate a single TTL-level signal containing information from both sensors (Figure 1). This design uses a 74HC123 monostable multivibrator, IC1, to form a free-running oscillator.....(design idea added 1/05)
Measure Inductance with DC Superimposed - 07/06/95 EDN-Design Ideas:.....(design idea added 3/03)
Measure nanoamps to ensure accurate computer clocks - (Video Design Ideas- EDN, 5/10/07  In this EDN Video Design Idea, Jim Williams, staff scientist with Linear Technology, explains why PC clocks are invariably wrong, and how engineers can surmount the extreme measurement challenge involved in solving the problem. (electronic design idea added 9/08)
Measure open circuited cables using a multimeter - 09/26/02 EDN-Design Ideas:  You can use a multimeter with capacitance-measurement capability to measure the length of wire or cable to an open circuit. The capacitance of a pair of wires (or a wire to a shield)is directly proportional to the length of the wire. If you know the capacitance per foot of wire, then you can calculate how far it is to the open circuit.....(design idea added 1/05)
Measure power line distortion with a mixed signal THD analyzer - 11/22/07 EDN-Design Ideas:  A mixed-signal total-harmonic-distortion-analyzer device measures the distortion of the mains ac voltage.....(design idea added 9/08)
Measurement methods - Application Note MiniCircuits.com  (app note added 04/05/06)
Measuring Input and Output Impedance - From the AC impedance triangle, the input or output impedance of a two terminal network can be determined by measuring the small signal AC currents and voltages. For the input, the voltage is measured across the input terminals and the current measured ....  (circuit design added 07/07/07)
Measuring Jitter in Digital Systems AN 1448-1 - Agilent Application Note  (added 6/06)
Measuring RF Voltages with a VOM - (schematic added 8/03)
Measuring self resonant frequency - Coilcraft RF Magnetics Application Notes -(added 6/06)
Measuring sensitivity of transponder coils - Coilcraft RF Magnetics Application Notes -(added 6/06)
Measuring the speed of light with Chocolate Chips 21 - Over the past week, I’ve been really busy with exams and projects. Trying to save time by finding the speed of light on Google, I stumbled upon an extremely interesting article on measuring the speed of light with a microwave. As any decent cook knows, microwaves do not heat evenly. In fact, this article explains their heating patterns are relative to the speed of light!...(project added 6/07)
Mercury Battery Replacement - There are many older battery-powered instruments on the surplus market that require mercury batteries but these batteries have been banned for environmental reasons. Simply substituting another battery type may give unsatisfactory…(circuit added 04/05/06)
Mercury Battery Replacement For Antique Instruments - I have recently been trying to restore a Radector radiation survey meter, vintage 1950s.  This instrument uses a 10 atmosphere argon filled ion chamber as the radiation detector and has an electrometer type vacuum tube sealed inside the chamber.  The design is simple and, for the time, quite elegant.  Unfortunately it....(added 05/08)
Method simplifies testing high Q devices - 02/21/02 EDN-Design Ideas:  The design of low-phase-noise oscillators requires careful attention to resonator unloaded Q. In the construction of a low-phase-noise, high-frequency oscillator, the goal is to achieve an unloaded-Q figure greater than 400 in a reasonable.....(design idea added 1/05)
Method Tests Cables - 10/17/02 EDN-Design Ideas:  Engineers have long known how to test a cable for continuity by simply connecting all conductors in series and checking with an ohmmeter. This method is sometimes impractical, however, because it cannot check for short circuits. The method shown in Figure 1 solves the short-circuit problem. Connecting.....(design idea added 1/05)
Mic Circuit Tester - Small oscillator to check mic & line circuits during sound setup.  440 Hz Tone generator for testing XLR microph1-lines (added 5/02)
MicroController functions as voltmeter - 05/10/07 EDN-Design Ideas:  PIC microcontroller and FETs enable a four-digit voltmeter.....(design idea added 9/08)
MicroController simplifies battery state of charge measurement - 04/26/07 EDN-Design Ideas:  (design idea added 04/07)
Microphone Polarity Tester - (electronic schematic / circuit added 4/02)
MIDI interface/cable tester - (circuit / schematic added 6/05)
MIDITester - (circuit / schematic design added 6/06)
Millen 90501 Secondary frequency standard schematic - ....(electronic circuit added 07/07/07)
Millen 90651 Grid-dip meter manual w/schematic - (circuit added 07/07/07)
Millen 90651A grid-dip meter schematic - ....(electronic circuit added 07/07/07)
Millen 90652 solid-state dipper schematic - ....(electronic circuit added 07/07/07)
Millen 90662A grid-dip meter schematic - ....(electronic circuit added 07/07/07)
Millen 90903 oscilloscope (new version) schematic - ....(electronic circuit added 07/07/07)
Millen 90903 oscilloscope (old version) schematic - ....(electronic circuit added 07/07/07)
Millen 90912 instrumentation oscilloscope schematic - ....(electronic circuit added 07/07/07)
MilliGauss Meter - The circuit provides an easy yet reliable way to detect the intensity of a.c. (or e.l.f.) fields around the home or workplace. It is doubly effective because it does not merely detect the electromagnetic radiation emitted by electrical appliances, but the electromagnetic energy actually absorbed by the body. The circuit in is a standard charge pump...(electronic design added 9/02)
Mini DDS direct Digital Synthesizer - (schematic added 8/03)
Missing Codes Tester Checks 16 Bit ADC in 7 Sec - 06/10/99 EDN-Design Ideas:  As the resolution of ADCs increases from 12 to 16 bits and higher, the difficulty in testing the "nomissing-codes "specification grows proportionately. To fully guarantee no missing codes for a 16-bit ADC requires testing all 2 16-1 possible output.....(design idea added 6/06)
Mixed Signal Testing using the IEEE 1149.4 STA400 - National Semiconductor Application Note  (app note added 2/06)
Modified Scope Probe Tests Surface Mount Assemblies - 09/25/97 EDN-Design Ideas:  (design idea added 3/03)
Modulated Laser Diode Tester - This circuit can either be used to test laser diodes or as a general purpose modulated light source. The circuit has an adjustable diode threshold current and an adjustable modulation frequency. The frequency can be adjusted from below 30KHz to above 50MHz. It is powered from a 9v battery. ….(designed by David A. Johnson)
Monitoring Additional Supplies with the ADM1062-ADM1069 Super Sequencers™ - AN-781 Analog Devices Application Note  (app note added 6/06)
Monitoring High Voltages with the ADM1062-ADM1069 Super Sequencers™ - AN-782 Analog Devices Application Note  (app note added 6/06)
Monitoring Negative Voltages with the ADM1062-ADM1069 Super Sequencers™ - AN-780 Analog Devices Application Note  (app note added 6/06)
Morse Monitor - (circuit / schematic design added 6/06)
MOSFET Tester - This testing procedure is for use with a digital multimeter in the diode test-range with a minimum of 3.3 volt over d.u.t. (Tony van Roon's diode-under-test).  If your multi-meter is less than that it will not do the test.  Check your meter manual for the specs. (Tony van Roon's electronic design added 6/06)
Moving coil meter measures low level currents - 03/03/05 EDN-Design Ideas:  (design idea added 5/05)  Although an analog moving-coil meter may lack the resolution and accuracy that a digital readout provides, a meter remains the display of choice for certain applications. A digital readout simply cannot provide information about a measurement's rate of change, and tracking a reading's trend is easier on an analog meter.
MPU temperature meter - Multi point temperature meter which displays tempertures to an LED display with time divided. This is good for monitoring temperature of PC components.  (added 6/06)
MPU temperature meter #3 - Multi point diode temperature meter to replace thermister temperture meter. This is for diode temperture sensors icludes on-die thermal diode of micro-processor.  (added 6/06)
Multi Wire Cable Tester - (electronic schematic / circuit added 4/02)
My Method for Measuring Gig/Tera Ohm Resistors -   ….(electronic schematic added 12/08)
Network Lead Tester - This was designed for confirming the continuity and correct wiring of computer network leads, but it can be adapted to check any lead with up to 8 wires by using appropriate connectors.....Designed by John Hewes (circuit added 06/07/08)
Nida Minilab 400 multi-purpose trainer information page - (added 07/07/07)
Noncontact Devicetests power supplies - 03/01/01 EDN-Design Ideas:  (design idea added 2/06)
NPN/PNP Transistor Tester - I designed this circuit about 30 years ago and still use it from time to time. It is powered from a 3v battery. It makes a tone when the transistor tests good. It can be used to determine device type (NPN or PNP) and the base, collector or emitter transistor pins. It can also test most transistors will still connected to a circuit. ….(designed by David A. Johnson)
NTSC Test Signal Generator - An accurate test signal generator for television calibration and measurements.  (added 6/06)
Off Line Telephone Tester - Here is a circuit of an off-line Telephone tester which does not require any Telephone line for testing a Telephone instrument. The circuit is so simple that it can be easily assembled even by a novice having very little knowledge of electronics. (added 4/08)
Opamp Design and Test Board - Quickly assemble an opamp circuit for testing.  Very easy and intuitive to use  (electronic schematic / circuit added 4/02)
Optimizing Bluetooth Device Battery Drain Measurements in Manufacturing - Agilent Application Note 1396  (added 4/08)
Oscilloscope helps obtain Bode plots in non 50Ω environments - 03/29/07 EDN-Design Ideas:  Vertical amplifier isolates high-Z circuit from low-Z network-analyzer input.....(design idea added 9/08)
Oscilloscope testing module (huntron circuit) - ….(circuit design added 03/08)
Owens Bridge Inductance Measurement Device - The circuit is a very simple RCRCRC filtered supply and a current source. The filtered supply provides 174 bolts at no load, and drops to 106 volts at 400mA. Ripple must be relatively low. In this supply, ripple is about 2 mV at 400mA load, so it is sufficiently filtered. Available voltage ranges from 154 volts at...  (added 8/03)
Testers:  #'s    A-B    C    D    E    F-G    H-K    L    M-O    P    Q-R    S    T     U    V-Z
 
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