Measuring and testing
Articles
Build an oscilloscope
- Build A Vector Network Analyzer - an essential tool for measuring the complex impedance of a circuit at a given frequency
- Coax connectors make low-cost test pieces - you can construct low-cost small test pices like filters, attenuators and terminators using coaxial panel jacks without pc boards or enclosures, design idea from EDN Magazine
- Counter Circuit Improves Oscilloscope Triggering - this prescaler circuit, when plugged into the scope's external trigger input, can provide reliable, low-jitter triggering for both older and modern oscilloscopes
- How to Build a 1 GHz Scope Probe for Next to Nothing - let's sacrifice input impedance and voltage sensitivity, and save money when probing at digital IC outputs
- Matching pads - describes some impedance matching circuit for measurements
- Modified oscilloscope probe tests surface-mount assemblies - small sizes and pad areas of surface-mount components make them difficult to probe but this simple tip helps it
- Multiplexer creates mixed-signal scope input - using two multiplexer ICs and some TTL logic), you can view eight analog or digital (or some of both) signals on the oscilloscope
- Probing High-Speed Digital Designs - shown circuit diagrams of norma 1:10 probe and 1 kOhm resistive input style probe
- RF Sampler - handly little gadget that lets you to "look" at the signal and frequency output of radio transmitter with oscilloscope
- Scope probe measures high frequencies - measuring clocks and critical signals accurately is often inconvenient and hard to do accurately with normal 10× probes, this article describes 100× probe that is easy to make and use, has a high bandwidth, and has a small (less than 1 pF) input capacitance
- Simple circuit provides timebase calibration - inexpensive and quick way to check the timebase speeds and linearity in vintage oscilloscopes
- Sniffer probe locates sources of EMI - this miniature special probe and an oscilloscope can help to locate and identify magnetic-field sources of EMI
- Trigger circuit locks onto one horizontal line - produces an oscilloscope trigger that synchronizes the horizontal sweep to a video signal that allows you to view any horizontal line by adjusting a potentiometer
- Voltage/Length EM-PROBES - DIY probes for checking electric and magnetic fields
Other oscilloscope links
- Bicotest Application Notes and Technical Bulletins - information on locating cable faults
- Defining Shorts & Opens - dealing with CATV distribution equipment and power supplies, we are constantly confronted with shorted and open components and circuits
- High Speeds and Fine Precision Knock PCB Traces Off Pedestal - knowing how to measure PCB trace impedances can help you optimize circuit performance from DC to gigahertz
- Introduction to Metallic Time Domain Reflectometry
- Measuring Cable Parameters - application note form HP which describes testing and characterizing cables, including characteristic impedance, capacitance per unit length, loss, and propagation velocity
- Signal Transmission Lines - describes basics and shows a transmission line demonstration setup
- TDR Tutorial - usage techniques and application notes
- TDR measurement of IEEE 1394 implementations
- The ABC's OF TDR'S - look also waveform examples
- Time Domain Reflectometry - paper published in Symposium and Workshop on Time Domain Reflectometry in Environmental, Infrastructure, and Mining Applications held at Northwestern University, Evanston, Illinois, September 17-19, 1994
- Time Domain Reflectometry Analysis
- Time Domain Reflectometry Analysis - analysis of a conductor which can be used for example to detect telephone tapping devices
- Time Domain Reflectometry Clearinghouse - many TDR papers, some on cable measurements and some for other applications
- Cable Reflection Tester - a schematic for a homebrew cable reflection tester from the December 1996 issue of Electronics Now, useful for checking coax cable runs for shorts or even impedance mismatches
- Cable tester is fast and cheap - simple microcontroller based cable tester verifies the correct wiring of the cable, up to 8 conductor cables
- Continuity Tester - audible output if resistance is less than 300 ohms
- Ring oscillator measures cable length - ECL exclusive-NOR gate (F100107) and a length of cable form a simple ring oscillator, the delay from the cable and the gate determine the ring oscillators frequency, 100m cable yields approximately a 1 MHz oscillation frequency
- Smart Continuity Tester - offers a short-circuit test current of less than 200uA and detects resistance values of less than 10 ohms
- 3 GHz Prescaler - will take a 0.1 - 3 GHz signal and divide it by 1000 so you can measure frequencies outside the normal range of your frequency counter
- Digital frequency counter by RU3AEP - 6 digits, up to 200 MHz
- Four Digit Frequency Counter - check also counter preset circuit for that counter
- Fréquencemètre 1 Hz - 10 Mhz - frequency meter circuit, text in French
- Fréquencemètre à microcontrôleur - Frequency-meter implemented with PIC microcontroller, text in French, try to access it using automatic English translation if you do not know French
- Frequency comparer produces binary results - uses four ICs to rapidly compare the frequency of two pulse trains
- Frequency comparator using 74HCT74
- Frequency to voltage adapter - in pdf format, text in Finnish
- F/V converter has high accuracy - high-accuracy frequency-to-voltage converter (FVC) demonstrates how a synchronous, charge-balance, voltage-to-frequency converter (VFC) can function as a single-supply FVC given proper biasing and level shifting
- Microcontroller measures high-frequency signals - circuit to to measure a frequency much higher than the internal clock frequency of the microcontroller
- Pulse period to voltage converter - converts a square wave input signal into a voltage proportional to the time between edges (period) of the signal, not the frequency, the range is from 100uS to to 10mS, which produces a voltage from 100mV to 10 volts
- Mixed-signal algorithm tests transducers - simple test procedure allows you to measure damping coefficient beta in electromechanical transducers, such as speakers, microphones, and seismic geophones
- Simple procedure tests transducer - testing electromechanical transducers can be as simple as measuring a dc voltage with this circuit, enables you to measure the damping coefficient ([beta]) of speakers, microphones, seismic geophones, and other transducers that exploit electromagnetic phenomena
Articles on RF measurements
Power and field strength meters
Simple RF detectors
Impedance measurements
RF spectrum analyzers
Signal attenuators
Antenna measurements
RF signal generators
- RF Signal Generator - cheap and fairly basic circuit to generate RF signals for realignment of radio receivers, operates from 150 KHz to 12 MHz
Other RF measuring tools
- Bias Tee - Bias tees allow you to insert DC voltages into your signal path (coax) without disrupting the existing signal in that path, for example for feeding active antennas
- Broaband Return Loss Bridge
Temeprature measuring devices
Digital temperature measurement devices
Computer based temperature measurements
Temperature limits detection and controlling
Temperature sensors adapting electronics
Selecting temperature sensors
- Temperature Sensor ICs Simplify Designs - When you set out to select a temperature sensor, you are no longer limited to either an analog-output or a digital-output device. There is now a broad selection of sensor types, one of which should match your system's needs.
- Tradeoffs in Selecting IC Temperature Sensors - A discussion of IC temperature sensors has become timely and important because electronic systems are increasingly dense, power-hungry, and hot. Temperature sensors also have a lot of gadget appeal. Many ICs perform highly abstract functions.
Other temperature measurement related circuits
Analogue display voltmeters
Digital display voltage meters
LED bar voltage display
Rectifier circuits
Peak detectors
RMS measurements
Voltage monitoring
Polarity testers
Impedance measurements
General semiconductor testing
Transistor testing
Capacitance measurements
Inductor measurements
Transformer measurements
Optoelectronics component testing
- Diode and LED Tester - simple and cheap unit for testing diodes and LED's for forward conduction and reverse blocking
Logic IC testing
- Logic ChipTester - ChipTester presented here is used with an IBM compatible PC, and will test nearly all logic devices, providing they operate from a single 5V supply and have no more than 24 pins, Originally published in the 1995 Cirkit Catalogue
- Audible Logic Probe - for testing TTL circuits
- Bus-request signal generates logic waveforms - this circuit generates 16-bit logic sequences with a resolution of 100 nsec
- Circuit adapts signals for visual perception - it is often advantageous to obtain a visual display of the activity of a digital logic signal
- Digital Data Display Unit - Display Binary and Hex data on this Hand Held device
- Logic Probe - uses a single CMOS IC and shows three logic conditions, High, Low and Pulsing
- Probing the heart of PC motherboards - information on measuring PC motherboards
- Pulse Masks Define Signal Limits - telecom networks and their components transmit digitized voice in signal formats dictated by industry standards
- Pulse Reading Logic Probe - This circuit uses LEDs to display logic states for high, low, rising pulse, and falling pulse in TTL circuits
- Scope/logic-analyzer team measures timing compliance of high-speed, synchronous designs - cross-triggering a logic analyzer and an oscilloscope yields optimal measurement information
- Simple logic analyzer pushes microcontroller to its limit - A simple logic-analyzer design is compatible with all versions of Windows and pushes the PIC 18C252 chip to its speed limit to achieve a 1-MHz sampling rate (Figure 1). The circuit can examine three channels of relatively low-speed logic signals that have infrequent, or sparse, transitions.
- Simple logic probe uses bicolor LED - probe can measure high, low, and high-impedance logic states, in addition to indicating switching logic states
- Triggering a Logic Analyzer on Complex Computer Buses Tutorial
- Use a PC to record four-channel waveforms - very simple four channel logic analyzer which connects to PC parallel port
- Calibration Forum - to discuss the problems related to the calibration of optical, electrical and photometric calibration in industry
- Ethernet 10BaseT simulator jig yields zero emissions - tool to evaluate emissions from Ethernet unshielded-twisted-pair (UTP) 10BaseT LAN-interface devices without contaminating the measured results with its own RF emissions, this cirucit generates 10BaseT equipment link test pulses without RF emissions so that 10BaseT equipment will keep sending data
- Fleapower circuit detects short circuits - a short-circuit tester that supplies a low current to the device under test (DUT) and also uses voltages lower than 100 mV to prevent conduction of semiconductors
- Multicore Cable Tracer - unit is designed to help when establishing the connections in multicore cables or when identifying a large number of cables contained in a trunking or conduit, supports up to 63 channels up to 100 meters or more, Originally published in ETI, August 1995
- Test Plug - circuit which indicates whether your mains socket is wired correctly, for 220-240V systems, Originally published in Electronics in Action, March 1994
General information on instrumentation
Insrumentation amplifiers
Voltage to frequency conversion
Current loop interfacing
Sensor and measuring circuit ideas
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