Circuits & Schematics - Supply

One of my electronics interests is building radios, particularly those featured in older UK electronics magazines such as Practical Wireless, Everyday Electronics, Radio Constructor, and The Maplin Magazine. Most of those radios are designed to run ...

In many applications, you would like to hold the speed of a motor constant, even as variations in the power supply voltage or mechanical load try to change its speed. In other applications, the average current to the motor needs to be limited, so ...

Single-cell lithium-ion (Li-ion) chargers are widely used, yet many practical designs rely on highly integrated ICs that conceal their internal operation. The type of Li-ion charger outlined in this design is, somewhat surprisingly, not readily ...

This easy-to-build PWM source is a handy testing tool for hobbyists, technicians, engineers and other RC-based device developers. I work at a university where I’m charged with designing and developing all manner of circuits and systems for ...

Convert a 4-20 mA signal to 0-20 mA and deliver it to a grounded load with no additional power supply needed. Recently, EDN kindly published a design of mine for a micropower 4-20 to 0-20 mA current loop converter ( Ref. 1 ). Shortly thereafter, in ...

Version 1 A single lithium ion battery cell needs 4.2 V from a current source to insure it is fully charged. A solar panel with just enough individual cells wired in series to produce the needed voltage would be more efficient than one with more ...

The iconic LM2917 tackles frequency-to-current conversion with (very) few externals. Almost exactly 50 years ago in June 1976, to be precise National Semiconductor introduced the LM29x7 series, offering deceptively simple monolithic solutions to a ...

There are many applications when a remote switch’s on/off status needs to be monitored. Reed relay sensors, toggle control switches and security alarms contacts are just a few examples. Routing a switch directly to a computer system hundreds ...

This project presents the design and implementation of a dual-fan PWM cooling circuit, integrating a compact and efficient power supply with intelligent fan speed regulation. The circuit consists of two main parts: a 6 W isolated flyback converter ...

This simple circuit can protect a sensitive electronic circuit from an accidental connection of a battery with a reversed polarity. The N-channel FET connects the electronic device to the battery only when the polarity is correct. The circuit shown ...