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 ...
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 ...
A self-heated Darlington transistor pair makes a simple, sensitive, and sturdy airflow sensor. But first an annoying non-linearity needs unbending. If you take a self-heated transistor in a TO-92 package and force it to hold a constant temperature ...
Converting frequency signals to loop current signals creates an economical result for process industry applications. Process industry applications commonly employ multiple motors. Their speeds are monitored by tachometers using magnetic pickups ...
A linearized output is a useful elaboration of a capacitive sensor design. But what if the circuit is located a significant distance from the control electronics? Recently, Design Ideas included a circuit ( Ref. 1 ) that comprised a simple analog ...
An only slightly less simple followup circuit also ratios sensor capacitance to a reference capacitor to measure micrometers this time linearly. A few weeks ago, Design Ideas published a simple circuit of mine that provides an analog interface to ...
The ubiquity of the 4 to 20 mA current loop in analog process monitoring and control creates possibilities for peculiar designs of circuits for unusual accessory functions. Figure 1 shows an example. It does precision conversion of 4-20 mA to 0-20 ...
This Design Idea describes a versatile test circuit for zener diodes after yet another misread zener diode had infiltrated the ranks of 1N4148 diodes assembled on a pc board. As a bonus, the circuit can serve as a moderate-voltage, power-limited ...