A sinewave is the simplest possible waveform, it is also one of the hardest to generate in pure form. Any impurity represents distortion, and that means added harmonics that make very low distortion measurements impossible...
Ultra-low distortion sinewave oscillator. Part 1
Finely tune the hue of blue-light sources
When coach cars of long-range trains comprised compartments for six to eight passengers, the passengers could choose either “white” or deep blue light. The blue light helped passengers sleep, even when they were not in full darkness. The circuit lets you set a hue of blue light...
Accurately simulate an LED
Solid-state-lighting applications are quickly moving into the mainstream. Although they are more efficient, the LEDs that produce the low-cost light often require a complicated driver circuit. Testing the driver circuit using LEDs, although easy, yields only typical results...
Battery simulator has variable ESR response
You may lack experience and hardware when designing battery-operated products. The battery life of a product can depend more on the ESR (equivalent series resistance) than the terminal voltage...
9 ppm distortion, quartz stabilized oscillator
A spectrally pure sine wave oscillator is required for data converter; filter and audio testing. Figure provides a stable frequency output with extremely low distortion. This quartz stabilized 4 kHz oscillator has less than 9 ppm...
Photosensing with ambient background
Trying to shield ambient light from your photo circuit is not a trivial task. You would think that you could just cover your circuit with your hands, but that is not a solution: Pulse oximeters depend on the translucency of flesh...
A single cell laser diode driver using the LT1110
Recently available visible lasers can be operated from 1.5 V supplies, given appropriate drive circuits. Because these lasers are exceptionally sensitive to overdrive, power to the laser must be carefully controlled lest it be damaged...
Method sets voltage in multiple-output converters
When you design a transformer for any power converter, you face several compromises. You must trade off core size against the number of primary turns and flux density...
Low-power, super-regenerative receiver targets 433-MHz ISM band
Designers often choose a super-regenerative receiver – despite its frequency instability and poor selectivity – for battery-powered, short-range, wireless applications in which power consumption is a major issue...
Adjustable 0 V to 5 V power supply
Linear regulator ICs are commonly used in variable power supplies. Common types such as the 317 can be adjusted as low as 1.25 V in single-supply applications. At low output voltages power losses in these regulators can be a problem...