Many low-cost and portable systems, including small consumer electronic products, operate from unregulated power supplies such as batteries or external, plug-in “power bricks.” These power sources sometimes produce lower-than-nominal output voltages...
Articles and news - 4
Simple circuit shuts off system when supply voltage is low
Precision DC motor speed control via pot or DAC
Ideally (in that magical land where theory and practice are the same thing), the speed of a permanent magnet DC motor is exactly proportional to the input voltage. But since real motors exist alongside us in the practical world, their behavior differs from this theoretical ideal...
Cancel PWM DAC ripple with analog subtraction
Every PWM DAC design needs analog filtering to separate the desired PWM duty-cycle-proportional DC component from unwanted AC ripple...
Smart ripple canceller offers near-zero dropout
Ripple cancellers, also known as ripple-eaters, gyrators, or electronic filters, are useful when a supply needs to be clean but the absolute supply voltage is unimportant. A typical application of these circuits is in class-A power amplifiers...
Inductor-based astable 555 timer circuit
The 555 multivibrator circuit has become a default choice of many hobbyists and even professionals in the past 50 years. Its pair of equations for frequency and duty cycle easily gives capacitor-resistor combinations which satisfy the required output...
Lowpass filter has improved step response
A common problem that arises when you design lowpass filters for signal conditioning is the filters' effect on the system's time-domain response. Because pushing the cutoff frequency lower slows the step response, the system may fail to recognize significant changes within a reasonable amount of time...
STMicroelectronics expands 5V op-amp family, to optimize power and signal-conditioning performance
STMicroelectronics has added the TSV782 high-performance dual op amp to its 5 V family, with 30 MHz gain bandwidth (GBW) and 50 µV (typical) input offset voltage for high-speed, high-accuracy signal conditioning...
Set DC-Motor Speed with Light-Controlled Microcontroller Circuit
This 8051 microcontroller-based control circuit adjusts the speed of a small permanent-magnet dc motor via photosensors...
Current-Output Circuit Techniques Add Versatility to Your Analog Toolbox
Although current mirrors and circuits such as the Howland current source are taught in analog circuit courses, a surprising number of engineers tend to think exclusively in terms of voltage when defining the output of precision analog circuitry. This is a pity, as current outputs offer advantages in a number of situations...
How to Measure Op-Amp Input Capacitance to Minimize Noise
While measuring op-amp input capacitance, what should you focus on? The answer is that you must ensure the measurement accuracy isn’t degraded by the stray capacitance and inductance of the PCB or test setup...