We recently saw how certain audio power amplifiers can be used as oscillators ( Ref. 1 ). This Design Idea shows how those same parts can be used for simple amplitude modulation, which is trickier than it might seem. The relevant device is the ...
LEDs need current to illuminate, and current usually flows through a power supply to an LED. A typical LED-driver circuit uses a transistor to provide current and a series resistor to decrease the voltage you apply to the LED. Unfortunately, the ...
Precision-matched resistors, diode pairs, and bridges are generic items. But sometimes an extra critical application with extra tight tolerances (or an extra tight budget) can dictate a little (or a lot) of DIY. Figure 1’s matchmaker circuit ...
Stephen Woodward, a prolific circuit designer with way more than 100 published Design Ideas (DIs), had his “80 MHz VFC with prescaler and preaccumulator” [ 1 ] published on October 17, 2024, as a DI on the EDN website. Upon reading his ...
We’ve seen lots of interesting conversations and Design Idea (DI) collaboration devising circuits for power switching using inexpensive (and cute!) momentary-contact SPST pushbuttons. A recent and interesting extension of this theme by ...
Implementing a simple digital-to-analog converter (DAC) by cascading a single pulse width modulator (PWM) and an analog low-pass filter is nothing new. Nor is applying to a filter the sum of the outputs of a most significant 2 N -count PWM and a ...
“Two halves make a whole” is a very old and often true maxim. For example, it’s almost always true when said about AC phase angle power control. You rarely want significant alternating half-cycle asymmetry due to the (usually ...
Check out this link for On Semiconductor’s datasheet for a line of “Zero-Cross Optocoupled Triac Drivers.” The ability to zero-cross when turning on AC line voltage to some loads may be advantageous. The following sketch in Figure ...
A simple circuit can improve the dynamic performance of a phototransistor for use in low- to medium-speed applications as fast as 100 kbps, such as optical isolation of an RS-232C serial line (Figure 1). In low-cost applications that require high ...
Lively discussions have sprung up here in editor Aalyia Shaukat’s Design Ideas regarding the limitations and quirks of, and design tricks for, the current control topologies shown in Figure 1. Figure 1. How to control amps of I OUT with mA of ...