Power-supply decoupler protects your UUT 05/10/2012
Detect and shutdown reverse polarity or overvoltage before damage occurs.
Build a digital PLL with three ICs 05/10/2012
A counter’s self-presetting feedback loop hunts for the center count.
Signal-powered switch connects devices 05/10/2012
Use a switch to selectively connect a terminal, personal computer, or any other originating device to one of four receivers.
Convert 1 to 5V signal to 4- to 20-mA output 04/19/2012
Precision analog current loop converter uses a matched resistor network.
Linearize optical distance sensors with a voltage-to-frequency converter 04/19/2012
Create the mathematical inverse of an analog voltage by converting it to frequency and measuring the period.
Use a transistor as a heater 04/19/2012
A temperature sensor and a hot transistor hold biological samples at a preset temperature.
Monitor circuit conserves battery energy 04/19/2012
Use a sampled-data technique to lower a monitor circuit’s average power consumption.
Simple circuit lets you characterize JFETs 04/ 5/2012
Measure the pinch-off voltage VP and zero-bias drain current IDSS to select matched pairs of JFETs.
Use a transistor and an ammeter to measure inductance 04/ 5/2012
Bipolar junction transistors transfer
a current from a lower-resistance
emitter to a higher-resistance collector.
You can use this property to measure
inductance.
Use a three-phase rectifier and voltage reducer for offline single-phase supplies 04/ 5/2012
Missing diodes create gaps to allow voltage reduction.
Lamps monitor beat frequency 04/ 5/2012
Synchronize an unknown frequency with a reference to obtain a zero beat by employing a visual monitor for the audio gap surrounding the near-zero frequencies.
Condenser microphone uses dc-coupled impedance converter 03/15/2012
Eliminate transformers and coupling capacitors in this self-balancing microphone interface.
Simple sawtooth generator operates at high frequency 03/15/2012
Use a digital logic gate to generate an analog waveform.
Dual regulator handles two input voltages 03/15/2012
Use a pair of MOSFETs to switch between 3.3 and 5V regulated voltage.
CMOS gate makes long-duration timers using RC components 03/ 1/2012
Use a common CMOS gate to make long duration timers using low-value RC components.
Microcontroller drives piezoelectric buzzer at high voltage 03/ 1/2012
Drive the buzzer directly from the μC’s I/O pins.
Conversion circuit handles binary or BCD 03/ 1/2012
Separate binary and BCD up/down counters permit both binary-to-BCD and BCD-to-binary conversion in one circuit.
Circuit simultaneously delivers square and square root of two input voltages 03/ 1/2012
Perform mathematical computations using analog techniques.
RC-timed shutoff function uses op amp and momentary switch 02/16/2012
Battery-operated instrument benefited from auto-power shutdown.
Simple diode serves as a sensor for a thermal probe 02/16/2012
A two-transistor thermal probe can be used to diagnose circuit problems, such as hot components and thermal runaway.
Use an integrator instead of coupling capacitors 02/16/2012
Level-shift a signal with an unknown dc offset to a known offset without ac coupling.
Use an LED matrix horizontally 02/16/2012
Using one 5×7 LED matrix horizontally instead of vertically allows the display of two characters instead of one.
Stable pulse generator uses matched transistors in a current mirror 02/ 2/2012
Inexpensive dual transistors work as well as do legacy matched pairs.
Implement an audio-frequency tilt-equalizer filter 02/ 2/2012
Developing the transfer functions lets you customize the filter.
Circuit provides 70 dB of AGC 02/ 2/2012
A comparator autoranges to ensure that the automatic-gain-control
section sees a signal between −60 and −25 dBm, keeping the FET in its
linear region.
Wireless temperature monitor has data-logging capabilities 01/19/2012
You can make a wireless temps system with two ICs.
Make an asynchronous clock for VPX-based PCIe systems 01/19/2012
Careful crystal selection and an FPGA are key to success.
Use a photoelectric-FET optocoupler as a linear voltage-controlled potentiometer 01/19/2012
The circuit takes advantage of an identical photo-FET as a feedback element.
Simple circuit tests twisted-pair cables 01/19/2012
Quickly test a cable containing twisted-wire pairs and detect open or reversed pairs, shorted pairs, and shorts between unrelated pairs.
Use a boost regulator beyond its rated voltage 01/ 5/2012
Use an external FET in a common-gate cascode configuration.
Measure an amplifier's THD without external filters 01/ 5/2012
Adding a secondary amplifier boosts the THD to measurable levels.
Use air-core-coil resistance to estimate inductance 01/ 5/2012
If the coil is tightly wound you do not need the number of turns to calculate inductance.
Current monitor uses Hall sensor 01/ 5/2012
Use a Hall-effect sensor to measure dc current in the range of 0 to 40A.
Control your holiday lights with a magic wand 12/16/2011
A magnet waved past a Hall-effect sensor does the trick.
Circuit provides more accurate multiplication 12/15/2011
Convert into and out of the sampled-data domain to get an accurate multiplication.
A few added components make a self-contained controller for 100A load 12/15/2011
Add a few components and you have a stand-alone piece of test gear.
Simple night-light uses a photoresistor to detect dusk 12/15/2011
You can adjust this battery-powered circuit for different levels.
Inexpensive VFC features good linearity and dynamic range 12/ 1/2011
A voltage to frequency converter circuit builds on the work of two analog greats.
Mains-driven zero-crossing detector uses only a few high-voltage parts 12/ 1/2011
You can get isolation with low power consumption using this simple circuit.
Build an op amp with three discrete transistors 12/ 1/2011
This simple ac-coupled design inverts, runs off a single supply and is self-biasing.
A diode ladder multiplies voltage under software control 12/ 1/2011
An eight-pin micro multiplies, monitors, and delivers a boosted voltage to a load.
Charger extends lead-acid-battery life 12/ 1/2011
A circuit that properly charges sealed lead-acid batteries ensures long, trouble-free service.
Add extra output to a boost converter 11/17/2011
The added output has its own voltage regulation.
Fabricate a high-resolution sensor-to-USB interface 11/17/2011
A precision analog acquisition system fits in your pocket.
Converters yield droop-free S/H circuit 11/17/2011
Use an ADC and DAC back-to-back to process signals up to 1 kHz.
Circuit detects rapidly falling signals and rejects noise 11/ 3/2011
Combine an op-amp and a logic IC to determine signal peaks beyond a set threshold.
Hack into a stopwatch to make a phototimer 11/ 3/2011
Two transistors create a pulse train to operate a stopwatch.
Comparator directly controls power-MOSFET gate 11/ 3/2011
Circuit switching point is independent of unregulated FET voltage.
AGC circuit uses an analog multiplier 11/ 3/2011
This automatic gain control works over the audio-frequency range.
Use a self-powered op amp to create a low-leakage rectifier 10/20/2011
An amplifier that works at 0.8V is key.
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