For containing large amounts of bulk capacitance, controlling inrush currents poses problems. The simplest approach involves placing an inrush-limiting resistor in series with the capacitor bank, but a resistor wastes power and adds a voltage drop...
Inrush limiter also provides short-circuit protection
High-Power White LED Driver Runs Battery-Operated Portable Lighting
Many people consider white LEDs to be the future of lighting. Strung together, several LEDs can replace an incandescent lamp or a compact fluorescent lamp. High-power white LEDs need a dc voltage of about 3.6 V at a current of about 350 mA to achieve full brightness...
Single-wire keypad interface frees microcontroller-I/O pins
If you use a microcontroller to detect a key closure, checking the states of (x+y) lines requires an equal number of I/O pins. Occupying only one free I/O pin, the circuit communicates with a microcontroller...
Reversed Capacitor Causes Motherboard Fires
Asus has recalled many of the company’s ROG Maximus Z690 Hero motherboards after reports that the boards could catch fire due to a capacitor that was aligned wrongly...
Reduce voltage-reference output noise by half
Reducing low-frequency (1/f) noise generated by an IC voltage reference can prove difficult. In theory, adding a lowpass filter to a reference's output reduces noise. In practice, a lowpass RC filter...
Germanium Dual-Boost Starts At 260 mV
No matter what portable power source you use, the lower the starting voltage your circuitry operates at, the better. A lower startup voltage also maximizes runtime...
Low cost, high-performance signal generator board
MikroElektronika has launched the Waveform 4 Click board – a member of its +1000-strong Click family of peripheral development boards – that operates as a signal generator for high-speed, high-dynamic-range, multichannel complex waveforms...
Simple Circuit Reduces Relay Coil Power
Fellow engineer Sanjay R. Chendvankar recently offered a novel way of reducing current through a relay coil. His idea utilized an unused normally closed pair of contacts of that relay...
Full-wave signal rectifier uses just one transistor
The simple circuit shown accomplishes full-wave signal rectification with only one transistor. This is done by exploiting the “gain reversal” phenomenon exhibited by a saturated bipolar transistor...
Tuning a Quadrature Encoder by Ear
The human ear is very good at detecting noise or missing cycles in a waveform, and since we have two ears, we can monitor two signals at once. I recently repaired an older lab instrument containing a quadrature encoder made with an incandescent lamp...
