Steve Woodward has authored over 50 analog-centric circuit designs. A self-proclaimed "certified, card-carrying analog dinosaur", he is a freelance consultant on instrumentation, sensors, and metrology freelance to organizations such as Agilent Technologies, the Jet Propulsion Laboratory, the Woods Hole Oceanographic Institute, Catalyst Semiconductor, Oak Crest Science Institute, and several international universities. With seven patents to his credit, he has written more than 200 professional articles, and has also served as a member of technical staff at the University of North Carolina. He holds a BS (with honors) in engineering from Caltech, Pasadena, Calif., and an MS in computer science from the University of North Carolina, Chapel Hill.
W. Stephen Woodward
Stephen Woodward
Areas of interest of the author: Measurement Interfaces Analogue Design Automation Microcontrollers Usage Supply Amplifiers Solar Signal Processing, Filters Oscillators Audio Light High Voltage ADC, DAC Digital Power Games Wind Energy Beginners
Publications on RadioLocman by the author W. Stephen Woodward:
- RS-232 meets voltage-to-frequency converter19-11-2024
- Negative time-constant and PWM program a versatile ADC front end18-11-2024
- Half & Half piezo drive algorithm tames overshoot and ringing12-11-2024
- 80 MHz VFC with prescaler and preaccumulator28-10-2024
- Preaccumulator handles VFC outputs that are too fast for a naked CTP to swallow22-10-2024
- DC-accurate, 32-bit DAC achieves 32-bit resolution21-10-2024
- Improved PRTD circuit is product of EDN DI teamwork10-10-2024
- The power of practical positive feedback to perfect PRTDs01-10-2024
- 20MHz VFC with take-back-half charge pump30-09-2024
- Take-Back-Half precision diode charge pump26-09-2024
- Brute force mitigation of PWM VDD and ground "saturation" errors23-09-2024
- Switch mode hotwire thermostat18-09-2024
- Digital pot can control gain over a 90 dB span like an electromechanical03-09-2024
- 8-bit PWM + 8-bit Dpot = 16-bit hybrid DAC29-08-2024
- Dpot pseudolog + log lookup table = actual logarithmic gain28-08-2024
- Keep Dpot pseudologarithmic gain control on a leash15-08-2024
- Synthesize precision Dpot resistances that aren't in the catalog07-08-2024
- Single supply 200kHz VFC with bipolar differential inputs24-07-2024
- Voltage inverter design idea transmogrifies into a 1MHz VFC18-07-2024
- The good, the bad, and the ugly of zero trims18-07-2024
- Solar day-lamp with active MPPT and no ballast resistors02-07-2024
- Portable thermal anemometer hot-transistor bias compensation nulls battery discharge droop27-06-2024
- Getting positive results from NTC thermistors with a simple passive interface25-06-2024
- I2C active pullup is power thrifty24-06-2024
- Relay and solenoid driver circuit doubles supply voltage to conserve sustaining power30-05-2024
- Improve thermal airflow sensor PSRR with just two resistors27-05-2024
- Double and invert 5 V to generate ±10 V using two generic chips and two bootstraps23-05-2024
- A groovy apparatus for calibrating miniature high sensitivity anemometers01-05-2024
- Efficient digitally regulated bipolar voltage rail booster26-04-2024
- Driving CMOS totem poles with logic signals, AC coupling, and grounded gates25-04-2024
- 15-bit voltage-to-time ADC for "Proper Function" anemometer linearization04-04-2024
- Charge pump halves voltage to double current "efficiency"27-03-2024
- Efficient voltage doubler is made from generic CMOS inverters14-03-2024
- Voltage inverter uses gate's output pins as inputs and its ground pin as output13-03-2024
- ∆Vbe differential thermometer needs no calibration06-03-2024
- Hotwire thermostat: Using fine copper wire as integrated sensor and heater for temperature control04-03-2024
- "Sub-zero" op-amp regulates charge pump inverter09-02-2024
- More gated 555 astable multivibrators hit the ground running23-01-2024
- Gated 555 astable hits the ground running18-01-2024
- A simple, accurate, and efficient charge pump voltage inverter for $1 (in singles)10-01-2024
- Adding one resistor improves anemometer analog linearity to better than ±0.5%29-12-2023
- New full-wave precision rectifier has versatile current mode outputs22-12-2023
- Single supply function generator outputs buffered squares, triangles, and sines13-12-2023
- Force/sense connection eliminates multiplexer on-resistance error08-12-2023
- Circuit transmits ARINC 429 data04-12-2023
- Simultaneously control gain on two independent channels with a single element pot23-11-2023
- Op-amp wipes out DPOT wiper resistance16-11-2023
- The DAC buddy09-11-2023
- 3-leg regulator in shunt mode makes variable power supply symmetrical30-10-2023
- Temperature controller has "take-back-half" convergence algorithm26-10-2023
- Adjust op-amp gain from -30 dB to +60 dB with one linear pot24-10-2023
- Low-cost precision adjustable current reference and application19-10-2023
- A 50 MHz 50:50-square wave output frequency doubler/quadrupler10-10-2023
- Minimizing passive PWM ripple filter output impedance: How low can you go?05-10-2023
- Make gain-control multiplexer RON and ROFF errors (mostly) disappear28-09-2023
- 1 kHz per degree Kelvin temperature sensor08-09-2023
- Flip-flop plus choke comprise simple and cheap inductive sensor06-09-2023
- Dual RRIO op amp makes buffered and adjustable triangles and square waves17-08-2023
- Light powers isolation amplifier27-07-2023
- Classic 3-leg adjustable regulators have a shunt mode? Who knew?24-07-2023
- 300 volt, 4 second, self-calibrating Shannon decoder DAC06-07-2023
- Self-heated ∆Vbe transistor thermostat needs no calibration04-07-2023
- Shannon decoder DAC meets UART29-06-2023
- Nonlinearities of Darlington airflow sensor and VFC compensate each other21-06-2023
- A "free" ADC22-05-2023
- Set DC input-stage gain/attenuation over a 96 dB range with PWM28-04-2023
- Squeeze extra resolution from an 8-bit DAC with Shannon decoder idea26-04-2023
- DAC (PWM) Controlled Triangle/Sawtooth Generator20-04-2023
- Adjustable regulator trimmer simple failsafe circuit18-04-2023
- 555 triangle generator with adjustable frequency, waveshape, and amplitude; and more!09-02-2023
- Transistor ∆VBE-based oscillator measures absolute temperature10-01-2023
- The Shannon decoder: A (much) faster alternative to the PWM DAC22-12-2022
- Cancel PWM DAC ripple and power supply noise24-11-2022
- CMOS flip-flop used "off label" implements precision capacitance sensor28-10-2022
- Precision DC motor speed control via pot or DAC12-10-2022
- Cancel PWM DAC ripple with analog subtraction11-10-2022
- Linearized portable anemometer with thermostated Darlington pair21-09-2022
- FemtoAmp offers extreme gain range & isolation13-09-2022
- Self-heated Darlington transistor pair comprises new air flow sensor23-08-2022
- New VFC uses flip-flops as high speed, precision analog switches02-08-2022
- Multiplexed, programmable-gain, track-and-hold amplifier has instrumentation inputs21-07-2022
- Flying capacitor and negative time constant make digitally programmable-gain instrumentation amplifier21-07-2022
- Inverted MOSFET helps 555 oscillator ignore power supply and temp variations19-05-2022
- Add One Resistor to Give Bipolar LM555 Oscillator a 50:50 Duty Cycle25-03-2022
- Input buffer and attenuator for sound card oscilloscopes extends low-end frequency response15-02-2022
- Circuit cancels interconnection resistance to enhance load regulation26-12-2021
- Series vs shunt linear voltage regulation for small solar-photovoltaic power supplies14-12-2021
- Series-Connected Transistors Use Differential Heating To Sense Airflow01-12-2021
- Quickly discharge power-supply capacitors08-05-2021
- Circuit for optical reflex sight adds automatic power-off10-03-2021
- Circuit controls intensity of reflex optical sights03-03-2021
- DPPs make nonvolatile microvolt DAC21-12-2020
- Digital potentiometer simulates log taper to accurately set gain12-02-2020
- Achieve precision temperature control with TEC Seebeck-voltage sampling03-12-2019
- Thermoelectric-cooler unipolar drive achieves stable temperatures03-12-2019
- Diodes derive logarithms and exponentials to optically sense AC/DC current20-10-2019
- Combine two 8-bit outputs to make one 16-bit DAC19-06-2019
- Synthesize variable in-circuit Rs, Ls, and Cs12-05-2019
- Pseudologarithmic thermistor signal conditioning spans wide temperature range20-11-2018
- Fast PWM DAC has no ripple09-10-2018
- Isolated Receiver/Converter Uses Multichannel Opto-Isolator18-07-2018
- Optically Isolated 4- To 20-mA Current-Loop Transmitter Is Accurate, Inexpensive05-07-2018
- Inverted dual-slope ADC boosts dynamic range28-03-2018
- Actively driven ferrite core inductively cancels common-mode voltage22-02-2018
- Linear wind-power meter compensates for temperature29-01-2018
- Circuit limits dV/dt and capacitor inrush at regulator turn-on23-01-2018
- Turn negative regulator «upside-down» to create bipolar supply from single source05-10-2017
- Square-root function improves thermostat26-04-2017
- Transistor linearly digitizes airflow31-01-2017
- Amplifier cancels common-mode voltage11-01-2017
- Fast-settling synchronous-PWM-DAC filter has almost no ripple09-11-2016
- Battery-powered amplifier has optical isolation03-11-2016
