To generate high voltages with proper insulation between the “hot node” and the rest of the circuitry, a car ignition coil can function in place of a high-voltage transformer. These coils have voltage ratings of approximately 20 kV, so ...
Professional condenser microphones require a 48-V supply to charge the internal capacitive transducer and power the internal buffer for the high-impedance transducer output. You can use a simple boost converter, a filter circuit to reduce ...
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 ...
The classical Schmitt trigger circuit that you'll find in textbooks provides some noise immunity, such as for the front end of magnetic pickup in position-sensor circuits (Figure 1a). You adjust the two threshold levels using R 1 and R 2 or R 2 ...
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 ...