Monthly Archives: February 2012

Mastech Single-Output DC Power Supply HY3003D 30V 3A

Posted by on February 28, 2012 No comments

Mastech HY3003D DC Power SupplyMastech HY3003D is a brand new lab grade DC regulated power supply. This highly stable, high quality DC power supply has an output continuously adjustable at 0-30V DC and 0-3A. What’s more, the unit is equipped with coarse and fine controls for adjusting the voltage and current outputs, making it extremely easy to set the output to your desired level. The unit comes with 2 backlit LCD displays, providing accurate readout for the voltage and current values.

Features & Specifications:

Adjustable outputs: 0-30V and 0-3A

* Coarse and fine controls for both current and voltage outputs
* Input voltage: 110V/60Hz
* Line regulation: CV <= 0.01% + 1 mV, CC <= 0.2% + 1 mA
* Load Regulation: CV <= 0.01% + 3mV, CC <= 0.2% + 3 mA
* Ripple noise: CV <= 0.5 mV RMS, CC <= 3 mA RMS
* Protection: constant current and short-circuit protection
* LCD reading accuracy: +/-1% for voltage and +/-2% for current
* Environment: 0-40C, relative humidity < 90%
* Size: 11.5″ x 6.5″ x 5.5″
* Weight: 12 lbs
* Warranty: 1 year

 

  • Adjustable outputs: 0-30V and 0-3A
  • Line regulation: CV <= 0.01% + 1 mV, CC <= 0.2% + 1 mA
  • Load Regulation: CV <= 0.01% + 3mV, CC <= 0.2% + 3 mA
  • LCD reading accuracy: +/-1% for voltage and +/-2% for current
  • Protection: constant current and short-circuit protection

More Power Supply Products

 

How to Choose a Digital MultiMeter

Posted by on February 20, 2012 2 comments

This article below is going to talk about how to buy a digital multimeter. Nowadays, DMM ( digital multimeter) prevail the electrical tester market, analog multimeter has lost its dominance.

Mastech MS8268 Digital Multimeter

 

1. Accuracy: if you are not a metrology engineer, so a standard accuracy is good enough, as most of DMMs now have the accuracy of 1% or better for DC ranges 2% or better for AC ranges. You should know that the analog multimeter usually has the accuracy of 2.5% or worse. So accuracy for Digital multitester is not the problem.

2. Input impedance : most of DMMs now have 10Mohm or higher for DC voltage ranges, 1Mohm or higher for AC voltage ranges. That is quite good, so this parameter is not a problem either.

3. Measurement features: most of DMMs can measure: AC voltage, DC voltage, DC current, AC current, resistance, continuity, diode check.
You may want some more features: capacitance, frequency, temperature, humidity, pressure, transistor hFE measurement

4. Automatic switching ranges: cheap Digital multimeters have no this feature, while it is very useful and safe, especially, when you need to measure the unknown high value of voltage, current. On the other hand, Digital multitesters with this feature also have good enough input protection, that is the most important.

5. Measuring ranges: most Digital multimeters have good enough wide ranges: DC voltage of 100mV to 700…1000V, AC voltage of 400mV to 600…1000V, DC and AC current up to 10A, resistance from tens to 30…40Mohm.
You may want the lower ranges of DC or AC voltage ranges, so check carefully with the DMM’s manufacturer documents. In general, the DMM itself cannot have higher ranges of measurement due to unstability. If you want higher ranges, you should look for the auxiliary attachments.

6. The other features, you should take into accounts:
- fast display rate. Most cheap Digital multimeter are bad in this feature: they response to the change of measured value very slow, and sometimes you cannot be more patient to wait the display changes.
- Big digit.
- With backlight.
- “Hold” function, to freeze the display.
- Auxiliary resistor divider for measuring the high voltage.
- Auxiliary clamp for measuring the high current.
- Output open-circuit voltage at the diode check: should be at least 3V. Be aware: some Digital multitesters use 2 x AA batteries, but this voltage is only 1.5V and practically useless. With higher voltage, you can easily test diodes, LEDs, darlington transistors, MOSFETs, …
- Ruggedness: cheap DMMs are fragile, and have no rubber holsters

Mastech – Leading Manufacturer of Electronic Measuring Instruments

Posted by on February 16, 2012 No comments
mastech-logo.jpg

MASTECH founded in 1987, is the world’s largest instrument manufacturer, is the world’s leading provider of electronic measuring instruments, one of the test instrumentation industry is well-known brand is recognized by the national brand-name high-tech enterprises in Guangdong Province products, electrical instrumentation industry, the main drafter of the national standard.

Technology innovation is the source for developing MASTECH. MASTECH Engineering R & D Center is the industry’s leading design institutions. Collection of a large number of high-quality corporate R & D personnel, with first-class sophisticated testing equipment, with many years of professional design, strive for global customers to design innovative, high quality, safe, durable, accurate and cost-effective technology products to meet customer needs, the same time, technological innovation and outstanding ability to provide global customers with a better ODM product design services.

Annual capacity of 3.5 million sets of various types of modern instruments, garden-style, large-scale production base is an important competitive advantage MASTECH protection. The company occupies more than twenty thousand square meters, with 1.5 million square meters of central air conditioning system clean plant, with advanced automatic assembly debugging flow-through and flexible production lines, advanced SMT workshop, injection workshop, silk screen shop, UL table pen test line production workshop, mold design and processing centers, and excellent facilities, measuring and testing center, excellent production environment, first-class production facilities, a huge capacity to provide a stable product supply, ensure that the company maintain industry leadership.

Enterprise management and quality management in a scientific and standardized is the core of successful development MASTECH. The company has a younger, better educated and more professional management team, the first in the industry with advanced ERP successful implementation of enterprise information management, from financial management, marketing, product development, manufacturing, logistics management and after-sales service and other aspects fully integrated information management system to ensure efficient operation of enterprises. The company also established by the international certification body TUV Rheinland certification of ISO9001 international quality standard management system, from supplier selection, incoming inspection to every aspect of production are strictly comply with international quality AQL inspection standard. Meet customer demand, the company is eternal quality, strict compliance with PDCA continuous improvement cycle mode, to ensure that customers with quality products.

Rich product chain, improve and upgrade is an important means to win market MASTECH. MASTECH to market successfully in many fields involving 200 kinds of products, has won widespread praise. Companies in the mass production of digital multimeter and clamp meter, based on the R & D and manufacturing is also an active electrical testing equipment, safety testing equipment, field instrumentation, analytical instruments, general instrument laboratory, environmental testing equipment, network cable tester and intelligent vehicle detector, and other high-tech products, to the leading and competitive world-class business capabilities. R & D and manufacturing in strict compliance with International Electrotechnical Commission has safety standards and environmental standards, products have received EU CE certification, some products also received the American UL, German GS certification for the expansion of global MASTECH laid a solid foundation.

Global marketing network and perfect after-sales service system is the driving force of the rapid development MASTECH. After twenty years of unremitting efforts, MASTECH established more than 700 global strategic partners, selling products in more than one hundred countries and regions in the world. In China, MASTECH brand has always been a leader trusted by customers, and an annual growth rate of 30% of the lead industry. MASTECH product not only is the customer’s first choice, but also instruments in the international market of China famous brand.

How to Test Capacitor With a Digital Multimeter

Posted by on February 15, 2012 1 comment

A capacitor is a circuit component that maintains voltage and discharges current over a matter of seconds when the voltage source is switched off. That’s different from a resistor, which loses voltage virtually instantaneously compared to a capacitor. This feature of dissipating voltage slowly is called the “performance characteristic” of a capacitor. Bigger electronic capacitors are shown in the images but capacitors can be included inside a computer chip with other components. Never turn your computer on immediately after turning it off because you may put too much voltage over a capacitor and burn it out: then your computer won’t function.

1 )
Set up your breadboard so that the long end faces you. Inspect the breadboard and find the letters A through J across the top and numbers 1 through 63 along the side. Place the battery connector on the battery.

2 )
Use an electrolytic capacitor with a 50-volt rating with a capacitance of 1 microfarad. Find the ground lead of the capacitor by looking for a “-” marking. Place that lead in position J20 on your breadboard. Place the other lead in position J25.

3 )
Measure the voltage decay of your capacitor. Place the black ground lead in position I20 to establish connectivity with the capacitor lead in J20. Note that continuity exists across each numbered row, including row 20. Turn your multimeter to VDC 20 (20 volts). Contact the black lead of the multimeter to the ground lead of the capacitor and the red lead to the other lead of the capacitor. Use alligator clips or hold them with your left hand.

4 )
Apply voltage to the circuit by placing the red lead of the battery into I20. Read the voltage across the capacitor, which should be approximately 9 volts. Glance at your clock. Remove the read lead of the battery from I20 and check the discharge of the capacitor. Watch the voltage over the capacitor drop to 0 over the course of eight to nine seconds.

5 )
Check continuity of the capacitor. Set the multimeter to the continuity check setting. Touch the black lead to the ground side of the capacitor and the red lead to the other side. If continuity exists (you’ll hear a long beep), the capacitor is short-circuited and should be discarded.

6 )
Set your digital multimeter to the highest ohms setting and apply it to the capacitor. Watch the meter approach 0 ohms and then start increasing. Keep the capacitor if it follows this general pattern.

7 )
Use the voltage decay test and the continuity check as your determinative tests and use the ohms test as a rough check.

8 )
Test a second electrolytic capacitor with a voltage rating of 63 volts and a capacitance of 6.8 microfarads. Construct a simple circuit with two resistors (each of 330 ohms resistance), the capacitor and a voltage source. Place one lead of resistor 1 in E63 and the other in E40. Place a lead of resistor 2 in D40 and the second lead in C25. Place the high lead of the capacitor in B25 and the ground (- or 0) in B23.

9 )
Put the battery ground lead (black) in A23. Put the red battery lead in C63. Set your multimeter to 20V and attach your red lead to the high capacitor lead (B25) and your black lead to the capacitor’s ground (B23). Remove the voltage source and watch the voltage decrease. Expect voltage discharge times ranging from one minute and 12 seconds to one minute and 17 seconds.

10 )
Note that the capacitance rating is within 20 percent, and there is often some variation.

How to Read a Digital Multimeter -Steps & Principles

Posted by on February 13, 2012 No comments

The digital multimeter is a useful tool for testing electronic circuits for integrity, voltage output, resistance and other electronic attributes. Knowing the principles of how a digital multimeter works will enable you to use this valuable testing tool with confidence.

1 )  Set the range of the multimeter. The multimeter’s readout depends on the scale that is chosen, which is dependent upon the current, voltage or resistance you are measuring.

2 )  Set the multimeter to register what you wish to measure, according to the specific instructions given for your model of multimeter. Once you have set the multimeter to the proper setting, make your tests according to the instructions. Note the reading.

3 )  Mark down, or notate, if necessary, the reading you have gotten. Be certain that you’ve set the multimeter to the correct range, and that the controls were set to measure the parameter you wished to measure.

Sinometer MAS345 Digital MultiMeter Review

Posted by on February 12, 2012 No comments

The Sinometer MAS345 is a digital multimeter with a computer interface included. This instrument is designed to accommodate all common functions of a DMM. It measures voltage and ampere of both AC and DC categories. It finds resistance in ohms. In addition to those it measures capacitance and temperature. It works for testing diodes, transistors and circuit continuity also. The brilliant extra feature is its computer interface function. So you get the scope to store and analyze the measured data on your PC.

Functions and Ranges

AC voltage ranges available on the DMM are 4, 40, 400 and 750V. Accuracy variation is from 1.2% to 1.5%. DC voltage has some similar ranges except the top one. It’s here 1000V. DC voltage measurement presents better accuracies that run from 0.5% to 0.8% only. Another vital function is ampere measurement. You may have 3 ranges in measuring both AC and DC currents. The spans are 4mA, 400mA and 10A. Accuracies here also mimic voltage measurement, which is a bit better in DC than in AC.

This multimeter can measure ohms in six ranges, starting from 400 ohms and finishing at 40Mohms. Accuracy for first five ranges is 1.2% and that for the last one is 3%. Your capacitance measuring tool has got two ranges and its correctness swings between ± 4.0%. You can measure a temperature as high as 750°C with this tool at an accuracy of 3.0%. The meter MAS345 is able to test continuity with buzzer signal. It can test diodes and transistors also.

Features

This DMM MAS345 has the features outlined below:

Auto range selection
Overload indication and protection
Conformity with IEC 1010 standard
PC-interfaced
1 month money return guarantee and 1 year warranty

This electronic tool serves your most of the testing and measuring purposes with acceptable accuracy. It looks great in an all black design. The package contains the instrument, test leads, software CD-ROM, RS232 cable and instruction manual. You may grab one for your everyday use, as the price is also within reach of most potential users.

Features

PC-interfaced digital multimeter with 3 3/4 digits LCD display, temperature and capacitance measurement
Auto ranging with very good sensitivity, resolution and accuracy
Overload indication and protection, low battery indication and back light
In full comformance with IEC1010 Standard
30 days money back guarantee & 1-year manufacturer’s warranty

Digital Multimeter Dictionary – From Wikipedia

Posted by on February 8, 2012 4 comments

ACCURACY

A measure of the difference between a multimeter’s reading to that of a primary, traceable standard. This is usually specified as a percent of reading plus a percentage of range (percentage of range is often referred to as display counts or digits). The percentage of reading is most significant when the reading is close to full scale, while the percentage of range is most significant when the reading is a small fraction of full scale.

Example Accuracy Calculation: 1VDC Measurement on the 4V Range

Displayed value: 1.000V

Accuracy:  4V Range = (0.5%rdg+2dgt)

Results:  (1.000V x 0.5%+0.2V*) = >0.7V

*2 dgt on the 4V range corresponds to 0.2V

Calculation:  1.000V >0.7V

True value:  In a range of 0.993V~1.007V

A/D (ANALOG-TO-DIGITAL) CONVERTER

An electronic device, often an integrated circuit, that converts an analog voltage to a digital value. All digital multimeters use an A/D converter to convert the input signal into digital information.

AUTO POLARITY

The ability of a meter to measure and display an input of either polarity without switching the input leads.

AUTO RANGING
The ability of a meter to switch among ranges automatically. The ranges are usually in decade steps.

AVERAGE RESPONDING

A measurement where the displayed value is proportional to the average of the absolute values of all input waveforms within a specified frequency range. It is calibrated in the rms value of a sine wave.

BANDWIDTH

The highest frequency signal component that can pass through input amplifiers and/or filters without being attenuated.

BIPOLAR

An analog signal range that includes both positive and negative values.

CAPACITANCE

In a capacitor or system of conductors and dielectrics, the property that permits the storage of electrically separated charges when potential differences exist between the conductors. Capacitance is related to charge and voltage as follows: C = Q/V, where C is the capacitance in farads, Q is the charge in coulombs, and V is the voltage in volts.

CAPACITANCE METER

Any meter that measures capacitance.

COLD JUNCTION

The junction in a thermocouple circuit that is held at a stable known temperature. Also known as reference junction.

COLD-JUNCTION COMPENSATION

A method of compensating for ambient temperature variations in thermocouple circuits.

COMMON MODE VOLTAGE

A voltage between input low and chassis ground of a meter.

CONNECTION PATH

The cables, connectors, switch cards, etc. between the device under test (DUT) and the meter. Its major parts are the conductors making the connection and the insulators isolating the conductors from the rest of the world.

CONVERSION

A process where a signal is changed from an analog to digital (A-D) representation, or digital to analog (D-A).

CONVERSION RATE

The rate at which sampled analog data is converted to digital data or digital data is converted to analog data.

CREST FACTOR

The ratio of the peak value to the root-mean-square (rms) value of a waveform.
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DIFFERENTIAL INPUTS

An analog input with two input terminals, neither of which is grounded, whose value is the difference between the two terminals.

DMM(Digital Multimeter)

An electronic meter that measures voltage, current, resistance, or other electrical parameters by converting the analog signal to digital information and display. The typical five-function DMM measures DC volts, DC amps, AC volts, AC amps, and resistance.

DUTY RATIO

The ratio of pulse width to repetition period. Also known as Duty Cycle.

DYNAMIC DATA EXCHANGE (DDE)

A Microsoft Windows standard mechanism for communication between programs. It allows your application to send and share data with other applications such as spreadsheets.

FLOATING

The condition where a common mode voltage exists between an earth ground and the meter or circuit of interest. (Low of circuit is not at earth potential.)

FOUR-TERMINAL RESISTANCE MEASUREMENT

A measurement where two leads are used to supply current to the unknown and two different leads are used to sense the voltage drop across the resistance.

GROUND

A common reference point for an electrical system.

IEEE

Abbreviation for Institute of Electrical and Electronics Engineers.

INPUT IMPEDANCE

The shunt resistance and capacitance (or inductance) as measured at the input terminals, not including effects of input bias or offset currents.

INSULATION RESISTANCE

The ohm resistance of insulation. It degrades quickly as humidity increases.

INSULATION

A material that does not significantly conduct electrical current.

INTEGRATING CONVERSION

An analog to digital conversion process where the output results in a digital representation of the integral of the input signal over a specified time interval.
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KELVIN CONTACTS

A means for testing or making measurements in electronic devices and circuits, particularly when low values are being measured. Two sets of leads are used at each test point, similar with respect to thickness, material and length; one set carries the test signal and the other connects with the measuring meter. The effect of resistance in the leads is thus eliminated.

LCZ METER

Inductance (L), capacitance (C), impedance (Z) meter. A general purpose meter for measuring component L, C. and Z. Sometimes called LCR meter.

LEAKAGE CURRENT

Leakage current is any unwanted current that flows when test voltage is applied. The ideal leakage current is zero. Leakage currents can originate in meters, cables, or the device being tested. Even high resistance paths between low current conductors and nearby voltage sources can generate significant leakage currents.

LINEARITY

The maximum deviation from a straight line between meter readings at zero and full range. It is expressed in percent.

MAXIMUM ALLOWABLE INPUT

The maximum DC plus peak AC value (voltage or current) that can be applied between the high and low input measuring terminals without damaging the meter.

MULTIPLEX

Connecting one meter to multiple devices under test or multiple meters to one device under test.

NOISE

An undesirable electrical signal from an external source such as an AC power line, motors, generators, transformers, fluorescent lights, CRT displays, computers, radio transmitters, and others.

NORMAL MODE REJECTION RATIO (NMRR)

The ability of an meter to reject interference (usually of line frequency) across its input terminals. Usually expressed in decibels at a frequency.

NORMAL MODE VOLTAGE

A voltage applied between the input high and input low terminals of an meter.
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OVERLOAD PROTECTION

A circuit that protects the meter against excessive current at the input terminals.

PEAK RESPONDING

A measurement where the displayed value is equal to the peak value of the input signal.

RANGE

A continuous band of signal values that can be measured or sourced. In bipolar meters, range includes positive and negative values.

RATED ACCURACY

The limit that errors will not exceed when the meter is used under specified operating conditions. It is expressed as a percentage (of input or output) plus a number of counts.

RATIO MEASUREMENT

The measurement of a signal input with relation to an external reference input.

READING

The displayed number that is proportional to the measured magnitude of the input signal.

READING RATE

The rate at which the displayed number is updated.

RELIABILITY

The ability of a device to perform within the desired range over a measured period of time.

REPEATABILITY

The ability of a meter to measure the same input to the same value over a short period of time and over a narrow temperature range.

RESOLUTION

The smallest value of input (or output) signal, other than zero, that can be measured (or sourced) and displayed. Also called sensitivity or minimum resolvable quantity.

RMS RESPONDING

A measurement where the displayed value is equal to the root-mean-square (rms) of the input signal, for all input waveforms having components within the specified frequency range and crest factor limit.

SHORT-TERM ACCURACY

The limit that errors will not exceed during a 24-hour period of continuous operation. Unless specified, no zeroing or adjustments of any kind are permitted. It is expressed as a percentage of reading plus a number of counts over a specified temperature range.

SIGNAL/NOISE RATIO

The ratio of the maximum signal that can be measured to the level detected with no signal present (noise level). It is expressed in decibels.

SINGLE-ENDED

The condition where the low terminal of a two-terminal meter is connected to a specific reference point, such as power line common, earth ground, or circuit common.

THERMOCOUPLE

A temperature sensor created by joining two dissimilar metals. This junction creates a small voltage as a function of the temperature.

TTL

Abbreviation for transistor-transistor-logic. A popular logic circuit family that uses multiple-emitter transistors. A low signal state is defined as a signal 0.8V and below. A high signal state is defined as a signal +2.0V and above.

WARM-UP TIME

The time required after power is applied to a meter to achieve rated accuracy at referenced conditions.

ZERO OFFSET

The reading (desired or undesired) that occurs when the input terminals of a meter are shorted.

Sinometer DT830B – Digital Multimeter User Manual

Posted by on February 5, 2012 No comments

DT830B series multimeters are pocket-sized 3 1/2-digit digital multimeters for measuring DC and AC Voltage, DC Current, Resistance and Testing.

Download DT830 Series Digital Multimeter Specification & Guide.

Sinometer DT830 User Manual