Here’s a fun project: Pop open an old microwave oven and scavenge the high-voltage transformer powering the cavity magnetron vacuum tube. Then use it to make yourself a Lichtenberg generator. But be sure there’s someone nearby to call an ambulance. Lichtenberg generators are used to create art and abstract objects by burning fractal patterns into […]
Commentary
Now or later? No time for time-of-use energy savings
Leland Teschler, Executive Editor One of the big justifications for smart home electronics and internet-of-things pipe dreams is a concept called time-of-use electricity billing. Long used for industrial concerns, the plan is to bring TOU billing to households, so they’ll be charged more for electricity they use during periods of peak use, less for juice […]
Keeping Cool
Preventing electronic circuits from getting too hot is not just about cooling but also trying to minimize the excess heat being generated in the first place. For a digital circuit that can be a case of reducing the voltage or clock speed, or dynamically altering the clock speed to suit what is required at the […]
Light detection and amplification
A common sensor requirement is to measure light. This may be for adjusting the brightness of a display or for instrumentation where accuracy is of importance and light levels could be very low. The light could be relatively constant or slowly changing, or it could be modulated at high speed. There are a number of […]
Ultra low power switching regulators
For micropower applications there are some interesting new devices around for helping power the circuitry. I am not thinking here about energy harvesting applications but low power battery operated devices where you don’t want the battery to go flat quickly when in standby but still need some regulated power to wake up a microcontroller, for […]
Choosing Ceramic Capacitors
It may seem a bit mundane but choosing ceramic capacitors can cause some problems and confusion. Ceramic capacitors have taken over from aluminum electrolytic capacitors and tantalum electrolytics in a lot of cases and even film capacitors but there are pitfalls. For example, the very low ESR (equivalent series resistance) of ceramic capacitors can cause […]
Understanding op amp input stages
Choosing an op amp and getting the best out of it involves some understanding of what is inside the chip, particularly the input stage. Simple bipolar input stage A conventional bipolar opamp will usually have a long-tailed-pair with two NPN or PNP input transistors as shown below. This explains the limited working range of a […]
Driving High Power LEDs
High power LEDs, particularly “white” ones are becoming increasingly used in commercial products from cars and domestic lighting to street lighting and with efficiencies which can exceed that of compact fluorescent lamps (CFL). That efficiency is likely to improve as the technology develops but you must also pay attention to your drive circuitry, not simply […]
Choosing and Driving Laser Diodes
Laser diodes come in a wide range of types and power. They are in DVD and CD players and writers, used in fibre-optic communications, visible laser pointers, distance measurement, printers, medicine and industry. The main decision points are: wavelength power pulsed or continuous. Wavelength depends on the application. If you want the laser as a […]
Choosing a brushless DC motor driver
By Chris Francis Brushless DC motors (BLDC motors) are quite different to drive compared to brushed DC motors. With a brushed DC motor you simply apply a voltage or pulse width modulated voltage and the motor will start turning (if possible) and increase speed with reducing torque until the torque/speed match the load. A brushless […]
