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Detailed entries for one subject from the INDEX TO HOW TO DO IT INFORMATION. |
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VOLTMETER & MULTIMETER sa AMMETER sa OHMMETER sa VOLTAGE MONITOR x DIGITAL MULTIMETER x DMM (DIGITAL MULTIMETER) x MULTIMETER x VOM (VOLT-OHM-MILLIAMMETER) xx ELECTRONIC TESTING xx METER (ELECTRONIC) How voltmeters, ammeters and other meters work. Report on assembling the Heathkit IM-16 solid-state voltmeter. Measuring a component's frequency response. Looks at four common sources of error. Includes a basic set-up for using a calibrated attenuator or "gain set" method of measuring frequency response. Upgrading your voltmeter. Convert a cheap 20k Ohm per Volt input impedance meter into a 10M Ohm constant impedance unit with this circuit. VTVM improvements include a battery eliminator and a calibration circuit. Improving Heath's IM-25 and IM-16 analog voltmeters. Report on the Fluke 8050A digital multimeter. Warning about spikes when using digital multimeters for audio applications. RMS AC voltmeter with dB converter. Build an A-weighting filter. Building a meter preamp to make measurements at very low (microvolt) signal levels using a vacuum-tube voltmeter, digital voltmeter, or oscilloscope. Linear AC measurements using a "diode". Using a synchronous rectifier circuit to measure AC voltage and current with DC meters. Circuit for an 8 channel 3.5-digit voltmeter built around the Motorola MC14433 3.5-digit analog-to-digital converter integrated circuit. Plugged into a minicomputer, it uses a simple program to display voltage readings on a video terminal. Four household circuit testers and what each will and won't do. Experimenting with Motorola's 68HC11 true single-chip computer. Part 6. SBC (single-board computer) applications. A look at MAG-11's binary output and how to use it A/D converter. Using the MAG-11 as a binary-display digital voltmeter and a bargraph photometer that measures foot-candles. Digital voltmeter uses a National Semiconductor DS8700 (ADD 2500) IC and a common cathode LED readout and a few other inexpensive parts. Modifying a digital panel meter (DPM) to measure voltages other than 200 millivolts (full scale). Single chip 4.5-digit digital voltmeter and continuity checker. RF Blocking probe for your VOM. Simple scope calibrator turns scope into peak-to-peak voltmeter. Ammeter adapter makes vacuum-tube voltmeter capable of measuring current. VOM meter saver. A diode bypass circuit around meter when full-scale deflection voltage is exceeded prevents damage to VOM meters. Selection and use of the VOM (Volt-Ohm-Milliammeter). Pocket size VTVM has VDC ranges of 5, 50, and 500 volts. Does not measure AC or resistance. Est. cost: $15. A FET millivoltmeter measures AC from 5 millivolts to 500 volts. Battery powered, large face, flat response from 10 cps to 1 mc, and input impedance of 1 megohm. Est. cost: $25. Using the vacuum tube voltmeter (VTVM). Calibrator turns an oscilloscope into a voltmeter. Adapter increases the input impedance of a VOM to that of a VTVM. Measure the output power of Citizens Band transmitters with this accessory for your VOM or VTVM. Est. cost: $4. Solid state VOM uses a field-effect transistor. 10-megohm input impedance, AC and DC ranges, 0.5 V scale, 9-volt battery powered. Est. cost: $25. Single-chip DVM (digital voltmeter). Has a full 4.5-digit display and allows measurement resolution of 10 microvolts. Also serves as a continuity tester. Mini metrology lab to study the science of electrical measurements (electrical metrology). Make high-accuracy DC measurements and calibrate other test equipment. Part 2. Build a null detector (null meter, DC null voltmeter), a very sensitive, center-zero voltmeter. Time-period adapter. Expand the measuring capabilities of your digital multimeter (DMM) with this easy to build and simple to operate accessory. Allows you to measure a low-frequency waveform accurately. Build this mini high-voltage probe. Increase your voltmeter's input impedance and measure up to 7500 volts with this easy-to-build accessory. Est. cost: $10-$20. Four essential test instruments. DC power supplies, function generators, bench digital multimeters, and frequency counters. An examination of their applications and key features. Tonal voltmeter. This circuit gives an audible indication of voltage levels (up to 15 volts DC). Using the 7107 integrated circuit chip. It is a combination analog-to-digital converter, reference voltage, timing clock, and decoder/driver circuit for 7-segment LED displays. Circuits shown for a digital voltmeter, DC current meter, resistance meter, capacitance meter, frequency meter, etc. Build a conductance adapter for your multimeter. Extend your DMM's range to include resistance in gigohms and current in picoamps. Build your own audio test gear. Five pieces of test gear, plus how and why they are used. (1) Audio signal generator. (2) Audio voltmeter. (3) Simple LED oscilloscope. (4) Distortion analyzer. (5) Wow-and-flutter meter. Part 1. An overview. Effective use of the VOM. A knowledge of the meter specifications, along with their proper interpretation, are required for effective use. FET voltmeter. Circuit for a transistorized version of the vacuum-tube voltmeter circuit. Uses the inexpensive field-effect transistor (FET). As accurate as most commercial VTVMs. How to read the decibel scale on VOM or VTVM meters. A simpler and more meaningful way to indicate signal voltage amplitide or voltage gain. Meter safety box automatically disconnects a VOM from the power circuit whenever its function switch is reset, as, for example, when switching from measuring voltage to measuring current. Circuit for an accurate, reliable, low-cost DC voltmeter. Measures 0-100 milliampere, 1 ampere, or 10 amperes for long periods without overheating, with voltage ranges of 0 to 10 and 100 volts. Accuracy of 2-3 %. Est. cost: $30. Low-cost precision calibrator for oscilloscope and VTVM. Solid-state VOM measures DC voltages from 150 millivolts full-scale to 1500 volts full-scale, and resistance from 10 ohms to 1 megohm. MOFSET utility 20-dB preamp for oscilloscope, AC voltmeter or VTVM. Also usable with microphones. VTVM battery eliminator. Simple regulated power supply that replaces C-cell ohmmeter supply. Method used by an Air Force laboratory to calibrate digital voltmeters. Explanation and use of meters. Volt, Ohm, Milliammeters, Meggars, and Galvanometers. Special VOM for photographers. Checks flashlight cells under load, B-C flashgun cells, high voltage electronic flash batteries and sync cords. Est. cost: $8. The hows and whys of voltage measurement. Most of the frequently-encountered problems of the experimenter and technician are successfully analyzed by making simple tests. Measuring capacitance with your VTVM. Capacitance adapter allows capacitance from .001 to 10 microfarads to be measured on a vacuum-tube voltmeter. Use any meter having a 3- or 5-volt range. Est. cost: $7. RF probe is a diode detector which converts RF energy to a measurable DC value. Est. cost: $4. HI-FET voltmeter will allow accurate voltage readings on low-impedance circuits. The device is less expensive than a commercial vacuum tube voltmeter. Est. cost: $20. MilAdapter, an accessory that allows you to measure electrical current on a VTVM. All new basic course in electricity and electronics. Understanding multimeters. Part 1. All new basic course in electricity and electronics. Understanding multimeters. Part 2. Build a field-effect transistor volt-ohm meter with a very high (20 megohm) input resistance on all ranges. Est. cost: $20. Basic course in electricity and electronics. How to measure electricity. Different types of meters and how to use them to measure voltage and current. Digital voltmeter (DVM) is built into a L'eggs brand panty hose container. It features a 3-digit LED readout. Goes from 00.0 to 99.9 volts dc (+ or -) in 0.1-volt steps. Has an input impedance over 1 megohm. Est. cost: $35. Super-accurate voltage source for calibrating your VOM or VTVM. Uses only two components (a mercury cell and a resistor). Replace the long test leads found on bench volt-ohmeters and similar equipment with coil-cords, those cords that are coiled up but can be pulled longer as needed. Convert photoflash cords into coiled test leads. Basic course in electricity and electronics. How to use a VOM to measure electricity. Build a precision voltage source for calibrating voltmeters and oscilloscopes. This battery powered source will deliver a nominal 2.45-volts DC. Elementary Electronic's basic course in electricity and electronics. The origins, theory, and use of the digital multimeter. Digital voltmeter for the dashboard of your car keeps track of your electrical system while you drive. Estimated cost: $28. How to use a volt-ohm meter. Using electrical testers. Tips on using a circuit analyzer, continuity tester, circuit tester, and multimeter. Tips on using a multitester to test electrical devices. Making milliohm measurements. Getting an accurate milliohm reading is easy when you know the correct method. Includes a schematic for an analog millivoltmeter. Selecting and using multimeters. Looks at analog, electronic, and digital versions. VOM range extender is designed to suppress any voltage up to the voltage of the battery used in the circuit. Converting from dot and bar indicators to other forms of readout. (1) Interface circuit allows a dot/bar display to be replaced by a numerical readout. Standing alone, it will also operate as a two-range, single-digit DC voltmeter. (2) Circuit converts a dot, bar, or digital display to a distinct audio tone which differs for each digit. Build the MOSFET voltmeter. Will measure voltage without scrimping on the readout or interrupting the test circuit's operation. Uses separate probes for measuring AC or DC current. VTVM Battery Substitute can be fed from an ordinary 6.3-volt filament transformer. Simple circuit feeds any applied voltage to the meter with the correct polarity. Capacitance adapter for your DMM (digital multimeter) lets you measure capacitance up to 2.2 microfarads. How to use a VOM meter. Troubleshooting electrical problems with a voltmeter. How to diagnose the most common auto and home wiring breakdowns. How to use a volt-ohmmeter. Basic electricity. Part 3. How to select a VOM, a tester every home needs. Basic electricity. Part 4. How to test voltage and resistance using a voltmeter (VOM). A short course in basic electricity. Part 5. How to make simple and safe resistance or continuity tests on home appliances. Meter demonstrator for classroom use can illustrate the function of a voltmeter or an ammeter. Tips on calibrating ammeters, ohmmeters, wattmeters, etc. Make an expanded-scale voltmeter (8 to 16 volts DC) to monitor an aircraft electrical system. Digital multimeters. Advice on selection and use when troubleshooting aircraft electrical systems. Instructions for using a VOM multimeter to check household and auto electrical problems. Hook up your PET computer to the world with this digital-voltmeter interface which lets you monitor and record readings from outside devices. Est. cost: $5. How to attach a fold-up wire stand to an inexpensive digital multimeter to hold it at a convenient angle for reading the meter. Circuit will allow you to measure capacitance on a VOM. Schematic for an amplifier for a VTVM to get accurate readings in the 0 to 20mV dc range. Circuit uses an LM308 integrated circuit. Twin electronic multimeter. Lab quality dual electronic multimeter with right-reading ohm scales. Features a linear resistance measurement scale. Twin meters allow you to measure voltage input and voltage output at the same time. Unit is powered by a 9-volt battery. Circuit for adding a meter to a power supply to measure the output up to 15-volts. Using and misusing multimeters. Here are a host of tips on getting the most service out of a multimeter. A true-rms adapter. This accessory lets you use a standard 3.5-digit DMM (digital multimeter) to measure true-rum voltages. Est. cost: $50. Thermometer accessory. A simple construction project lets you measure temperatures (Kelvin, Celsius or Fahrenheit) with any voltmeter. Measure high-frequency AC volts. Probe/voltmeter measures rms volts from 10 Hz to beyond 10 MHz and also functions as an amplitude-modulation detector. Digital measuring system. Build a highly accurate, low-cost 3-digit panel meter that serves as the basic building block for a wide range of speciality add-on function modules (digital multimeter, tachometer, thermometer, etc.). Measure voltage using a personal computer by adding a voltage-to-frequency converter onto an input port line. Temperature probe for your multimeter can measure down to 0 degrees and below. Frequency-counter adapter for digital multimeters. Frequency-to-voltage converter enables almost any waveform up to 1 MHz to be read accurately on a DVM or DMM. High-current shunt for DMMs (digital multimeters) extends current-measuring capability beyond the usual 10 amperes. Troubleshooting with dc voltmeters. Helpful hints for getting the most out of your multimeter's dc voltmeter mode. An audible AC/DC voltmeter sounds a tone whose frequency is proportional to the voltage being measured. Four input ranges are 200 millivolts, and 2, 20 and 200 volts. Digital milliohmmeter adapter lets you accurately measure less than 1 ohm with a digital multimeter (DMM). How to use DC voltmeters. Some useful tricks of the trade for getting the most out of your meter. A precision thermocouple thermometer. Voltmeter accessory lets you measure temperature with one-tenth-degree resolution. A maximum/minimum voltage detector. This voltmeter accessory tracks highest or lowest voltage, light, or other physical parameter levels for testing, troubleshooting and other applications. Tonal voltmeter. This circuit will give an audible indication of voltage levels. Mini high-voltage probe. Increase your voltmeter's input impedance and measure up to 7500 volts with this easy-to-build accessory. Est. cost: $20. Field-effect transistor voltmeter. Simple neon tube device tells approximate voltage. Miniature (5"x4"x3") VTVM has a constant resistance of 10 megohms on all ranges. Battery powered. Replace flashlight cells in VTVMs with a nickel-cadmium battery which will be recharged as the VTVM is used. VOM range splitter. Double the number of voltage ranges on your multimeter with this accessory. Multipurpose FET signal tracer. Can be used as a millivoltmeter, output meter, microphone preamplifier, auxiliary audio amplifier, tape recorder monitor, etc., as well as a sensitive signal tracer. Simple adapter to make a VOM act like a $200 transistorized voltmeter. Battery powered adapter uses a field-effect transistor and makes the synthetic VTVM independent of a 117-volt power line. Est. cost: $10. Direct-current electronic voltmeter. Almost non-loading voltmeter measures from 0.5 to 150 volts. This unit is ideal for testing semiconductor circuits because of its input resistance of only 1 megohm-per-volt on the lowest ranges. Est. cost: $20. Measure AC amps and watts with a VOM. Adapter to measure up to 1,000 watts or 10 amps AC. Circuit for a millivoltmeter with a full-scale sensitivity of only 10 millivolts. Uses an integrated circuit. An expanded scale AC voltmeter that reads between 90 and 130 volts is useful for monitoring household current. Adapter to improve the sensitivity of an ordinary volt-ohmmeter. Adapter will convert it to high-input-resistance (10 megohms) and give it two more low voltage ranges (0.5 and 0.1 volt full scale). Digital readout volt-ohmmeter. Self-zeroing and self-calibrating, three voltage scales (0-2, 0-20, 0-200), and four ohm scales (from 1 to 200,000). Est. cost: $80. An accurate audio voltage calibration standard to adjust VTVM or oscilloscope. Est. cost: $35. Instrument sensitivity booster (preamplifier) extends range of oscilloscope or VTVM. Adapter for a VTVM to measure extremely high resistance (up to 50,000 megohms). Millivolmeter designed to measure FET circuits without loading. Input resistance is 100 megohms with a 12 to 15 pF capacitance. Assemble a digital volt-ohmmeter plug-in module for the digital measurements lab featured in the November 1970 issue. Voltage measurements to 1999 volts DC and resistance from 1 ohm to 199,000 ohms. Est. cost: $30. A discussion of the evolution and uses of VOMs, VTVMs and TVMs. Constant-current circuit can be used with your VTVM to provide a linear-scale ohmmeter. Low-cost millivolter. Measures between 1 mV and 1 volt full scale. Can also be used as AC voltmeter. Resistance of 10,000 ohms/mV. Linear-scale ohmmeter covers from zero to 10 megohms in seven ranges. Unit also measures 3 ranges of dc millivolts (10, 100 and 1 volt) at 10 megohms per volt. Surplus D'Arsonval movement meters are easily converted to special-purpose voltmeters and ammeters. How and why to use a VTVM or VOM. This front end circuit for a digital multimeter (DMM) will turn it into a frequency counter. Range expander increases sensitivity by 10 or 100 times so you can measure low-millivolt AC and DC voltages. Can also be used on decibel scale. Build an auto-polarity and auto-zeroing digital multimeter. Est. cost: $100. Put your multimeter to use testing semiconductors, SCR's, triacs and your car. Build the minivolter. Measures from 500 microvolts to 100 volts full-scale in 12 overlapping ranges. Doubles as an ohmmeter down to 0.02 ohm. Use to measure current down to 10 mA. Est. cost: $20. This converter turns a digital frequency counter into a highly accurate digital VOM without modifying the counter. Has four ranges of ac & dc voltage readings (5, 50, 500, 1000) and five ranges of resistance (500 ohms, 5, 50, & 500 kilohms, 5 megohms). Calibrator circuit for a VOM allows you to check voltage, current, and resistance scales. A dual-polarity dc meter circuit. The meter will always go upscale, regardless of the polarity of the leads. Battery eliminator circuit for 1.5-volt batteries in a VTVM. Build a high-frequency voltmeter. Measures from dc to frequencies over 20MHz at amplitudes up to 90 volts in five overlapping voltage ranges. Est. cost: $25. Build the Audio Detective, a sensitive ac voltmeter which is very useful in troubleshooting an audio system. Has four ranges (0.005, 0.05, 0.5, and 5-volts). Meter is battery powered and small in size. Update your multimeter with a CMOS millivolter. Convert any voltmeter into a high-sensitivity input meter for low millivolt measurements using this amplifier probe that plugs into the standard input of any voltmeter rated at 1000 ohms (or greater) per volt. Est. cost: $12. LED bargraph readouts. Measure voltage, resistance and frequency with a row of lights which show trends (direction) better than meters with needles and less expensively than digital readouts. Circuits for several types of meters shown. Multimeters for electronics. Part 1. A look at traditional VOM's and analog-type electronic multimeters. Multimeters for electronics. Part 2. Digital multimeters. Circuits for a 2.5-digit and 3.5-digit digital voltmeter able to be built by the average experimenter. Build a 3.5-digit multimeter with either LED or LCD displays, plus a variety of options including a temperature probe. Est. cost: $50. Build a true rms voltmeter. Measures effective ac voltage rather than the usual average values. Est. cost: $30-$70. Buying the right digital multimeter. Understanding the specs, operating charecteristics, and special features of DMMs. Measuring large currents with a DMM. Use a high-current shunt to measure tens or hundreds of amperes. How to make the shunt. Single-LED analog meter uses a multicolor LED which changes color in response to input voltage. Circuit to enable an analog meter to measure ac and dc of either polarity. Low-ohms adapter. Accurately measure resistances down to 0.01 ohm with this low-cost plug-in adapter for any common digital multimeter. Audio millivolt meter features a high input impedance which assures that the circuit does not load down the unit under test. Expanded-scale voltmeter swings from 0 at 10 volts to full scale at 15 volts. Meter-range extender circuits that increase the sensitivity of an analog current meter. (1) Amplified DC microammeter. (2) Low-voltage voltmeter. (3) Meter-calibration circuit. (4) Low-range ohmmeter. All about meters. What you need to know to design ammeters, voltmeters, and ohmmeters. Does your meter lie to you? Learn all about the limitations of multimeters. AC line-to-multimeter adapter can make checking and monitoring line voltage safer. Turn your personal computer into a digital voltmeter for automated testing, to record readings over time, etc. Est. cost: $25 (kit). Sample-and-hold circuit makes a reading of an instantaneous voltage and holds that reading for a short period of time. High-voltage probe extends your DMM meter's range when working with high-voltage (up to 10,000 volts) or high-impedance (up to 100-megohm) circuits. Audible voltmeter circuit can be used to test for AC or DC voltages (between 4 and 200 volts) in a circuit. Expanded resistance ranges for your DMM (digital multimeter). Two simple devices let you take readings on much lower or higher ranges. Circuit for a negative-peak holding voltmeter will measure cranking voltage while starting an automobile. Handles 4 to 16 volts. Build a wireless DC volt probe (voltmeter) which eliminates test leads by using your body as part of the signal path. Using digital panel meters to enhance the look and performance of your next project. Circuits include: (1) AC power supply, (2) DC-to-DC supply, (3) DC ammeter, (4) automobile voltage monitor, (5) digital DC voltmeter, and (6) low-ohms meter. Op-amp applications. (1) CMOS-interface driver, (2) dual-voltage supply, (3) AC amplifier, (4) adjustable comparator, (5) dual-voltage comparator, (6) four-level voltage detector, and (7) voltage window. Build an active high-impedance probe to get more accurate readings from your DMM (digital multimeter). A collection of troubleshooting circuits. (1) Voltage testers. (2) Polarity indicator. (3) Continuity tester. (4) Transformer tester. (5) Meter resistance tester. (6) Intermittently-open circuit tester. Hot series test box replaces VOM. Voltmeter and ammeter circuits to measure voltage and current in ranges of .1, 1, 10 and 100 volts DC 50 microamperes and 1, 10, and 100 milliamperes. A review of various test meters which the home repairman can use to test home appliances. Build a VOM helper. Make it easier to measure printed circuit board amperage with a VOM meter by means of this simple "helper" board which provides 2 larger attachment points for the meter probes. Automobile voltmeter monitors your cars electrical system. Voltage is picked up from cigarette-lighter plug. Voltage is displayed on meter and on three lamps (red, yellow, green). Estimated cost: $17. How to use an ohmmeter (VOM) to test and troubleshoot home appliances. Nine-in-one troubleshooter does the work of nine individual test meters by means of one universal meter coupled with six interchangeable test modules. Part 2. Automotive tachometer/dwell meter and multirange volt-ammeter. Voltminder. An electronic meter to check the entire electrical system of car or boat. How to buy and use a VOM (volt-ohm-milliammeter). How to prevent appliance breakdowns. Perform regular checkups of home appliances with a VOM. Table of checkpoints and scale settings to use for testing. Using a VOM meter to troubleshoot your car's ignition system. Tips on selecting a VOM (volt-ohm-milliammeter) for appliance diagnosis around the house. Analog voltmeters. Part 1. A rundown on types available, their features, specification and applications. Analog voltmeters. Part 2. Analog voltmeters. Part 3. Servicing with multimeters. Hints on meter selection and use for electronic servicing. What you should know about digital multimeters. Build a 3.5-digit DMM (digital multimeter). Circuit starts out as a DPM (digital panel meter) that is then converted to a digital multimeter through the addition of some voltage-divider and current-shunt circuits. Est. cost: $50. Selecting a digital multimeter. What you should look for. LED bar graph universal indicator. Bar graphs are replacing analog meters as voltage-level indicators. Here's how the basic LED bar graph works. A single IC from National Semiconductor, the LH0091, adds true RMS measurements of voltage to a multimeter. Build a digital thermometer. Accessory converts a digital voltmeter into a thermometer for monitoring semiconductor case temperatures, photo chemicals, etc. Accuracy of 0.5-degrees over a range of -55 to +150 degrees. Est. cost: $40. Build an inexpensive expanded-scale voltmeter to monitor ac line voltage. Audio test station. Part 1. A series of articles describing the operation, design and construction of Fidelity Sound's model 101 Audio Test System kit. The unit consists of a power supply, two sine/square/triangle function generators, pulse generator, frequency counter and AC voltmeter. Est. cost: $650 (kit). Audio test station. Part 2. Power supply and timebase circuits. Audio test station. Part 3. Pulse generator, sweep shaper, and audio sweep generator. Audio test station. Part 4. Theory of operation and the construction of the voltmeter and digital frequency meter sections. Audio test station. Part 5. Step-by-step through the calibration process. Build this 4.5-digit precision digital multimeter. Includes temperature and true-RMS capability. Est. cost: $199. LED bar-graph display. Eight simple electronic gadgets which use this device, including expanded-scale voltmeters. Two new IC's from RCA make digital voltmeter design a cinch. Typical circuits shown. 3.5 digit DMM (digital multimeter) to build. New dot and bar-graph display driver ICs. How they work and typical circuits for audio-level meters, expanded-scale voltmeter, and similar meters. How to modify the full-scale reading of an existing voltmeter or ammeter. Add-on accessory for your digital or analog multimeter allows resistance measurements as low as 0.001 ohm. Est. cost: $42. Circuit for a simple RF sniffer which is used with a digital voltmeter. Build an analog voltmeter with a scale equivalent to one 36" long. Features reverse-polarity, over-load protection and a special circuit for AC. Meter adaptor circuit for a VOM. It increases the meter's input impedance considerable and can be used with meters having sensitivities as low as 1000-ohms-per-volt. DMM add-on lets you read resistance above the 20 megohm range. Circuit for a "voltage freezer" which reads and stores the voltage (freezes the meter) even after the probes are removed. Two compact DVM's (digital voltmeters). Equip your bench power-supply with its own 4-digit digital voltmeter. Est. cost: $25. Build this digital voltmeter for your car's dashboard. Est. cost: $30. How to use digital panel meters to measure voltage, current, resistance, capacitance, frequency, temperature, etc. Part 1. Voltage, current and resistance meters. Making true measurements of RMS values of AC voltages using RMS-to-DC converter IC's. What's new in DMM's (digital multimeters). Temperature measuring add-on for your DMM. Use your digital multimeter as a precision digital thermometer. Bargraph voltmeter for your car. Est. cost: $25. Purpose and meaning of the "half digit" found on many multimeters. Simple converter will add true-RMS (root mean square) capability to any VOM or DMM. Est. cost: $20. Circuit for a basic analog log amp built around a single op-amp. Called a "transdiode" circuit. Used to convert a linear-voltage input into a log-arithmic output to drive a meter. Op-amps show their versatility in instrumentation circuits. Includes circuits for rectifier, peak detector, AC/DC converter, voltmeter, ammeter, ohmmeter, voltage reference, and power supply. Circuit for an audio level voltmeter having a range of 0 to -80 dBm. Accepts audio levels as low as ten microvolts. Use it to calibrate microphones and speakers, or as a receiver "S" meter. Choosing the right test probe for your digital multimeter. Experimenting with PC-based test equipment. Part 2. Volt/ohmmeter. Working with LED display drivers. Using the National Semiconductor LM391X and LM2917 series IC's to build moving-dot and bar-graph voltmeters and frequency-to-voltage converters. Part 1. LM3914-series drivers and 7-segment display systems. Buyer's guide to digital multimeters (DMM's). Working with LED display drivers. Part 2. Seven-segment display driving techniques. Ohms range expander adds a X100K resistance range to many multimeters (VOMs). Est. cost: $6. VTVM dry cell eliminator. A transistorized voltage regulator powered by the low-voltage winding on the VTVM power tranformer. This unit replaces the 1.5-volt cell used in most VTVMs. Est. cost: $3. Two-tube audio generator and audio voltmeter. An adapter to turn a multimeter into a digital circuit tracer. Est cost: $4. Test-lead, polarity-reversing switch for a VOM and VTVM. Est. cost: $2. Troubleshooting your automobile ignition system with a digital multimeter. Modular test instruments. Part 1. Build your own voltmeter boards and power supply boards which will be incorporated into other instruments. Bar graph voltmeter circuit is a cheaper and more practical alternative to buying a digital multimeter. Simple modification converts the Fluke Model 75 multimeter to include all the features of the top-of-the-line Model 77. Low-frequency AC-to-DC converter facilitates the measurement of AC signals with frequencies lower than 20Hz using a digital multimeter. Converting Radio Shack's sound level meter to also function as a millivolt (mV) testmeter to measure loudspeaker response. Using a voltmeter (multimeter, multitester, volt-ohm-meter) to troubleshoot electrical devices. | |||||||||
Copyright © by Norman Lathrop Enterprises. All Rights Reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means (electronic, mechanical, print photocopying, recording or otherwise) without the prior expressed permission of Norman Lathrop Enterprises, except as permitted by law. |
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