Circuits & Schematics Diodes

1. 4-20mA to 0-20mA converter sips mere microamps
   Stephen Woodward
   Circuits Analogue Design Interfaces Diodes AP4310A
   Circuits for converting 4 to 20 mA analog current loop signals to 0 to 20 mA may be hot topics, but hot implementations of those circuits are not. Circuit designs for conversion of 4 to 20 mA analog current loop signals, which are ubiquitous in ...
   Jun 23, 2026
2. N-ch and P-ch transistors form push-pull driver
   David A. Johnson
   Circuits Beginners Diodes ZVN2106A ZVP2106A
   This circuit can produce high speed output signals with fast rise and fall times. The unique charge pump action allows the voltage of the upper P-ch device to range from millivolts to hundreds of volts. The output current is only limited by the ...
   Jun 9, 2026

3. Circuit protects from battery polarity reversal
   David A. Johnson
   Circuits Beginners Supply Diodes ZXM61N02F
   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 ...
   Jun 9, 2026
4. Transformerless 85-260VAC to 12VDC-0.2A power supply
   Hesam Moshiri
   Circuits Supply Diodes AL17150
   Whenever you hear the transformerless supply term, you initially imagine the capacitor-based solution: a high-voltage non-polarized capacitor in series with the mains line, a bridge rectifier, a Zener diode, and a filtering electrolytic capacitor. ...
   Feb 12, 2026
5. Power bank "Keep-alive"
   Tirdad Sadri Nejad
   Circuits Beginners Supply Diodes NE555
   A simple module to keep power banks from turning off, when your DIY circuit draws low currents. A simple power bank keep alive module. As the name is already suggesting, this module keeps power banks from auto turn off, when the load current is too ...
   Oct 1, 2025
6. Use a three-phase rectifier and voltage reducer for offline single-phase supplies
   Alberto Abal Pena Carlos Castro-Miguens José Benito Castro-Miguens Marcos Pérez-Suárez
   Circuits Supply Power Diodes TL431
   Some industrial applications require you to feed a low-power dc/dc converter from a three-phase source and possibly to deal with line-to-line voltages of 200 or 400 V rms. Further, the neutral terminal of the ac source may be unavailable for ...
   Jun 23, 2025
7. Precision programmable current sink
   Stephen Woodward
   Circuits Analogue Design Supply Diodes TL431
   The TL431 has been around for nearly 50 years. During those decades, while primarily marketed as a precision adjustable shunt regulator, this legacy device also found its way into alternative applications. These include voltage comparators, audio ...
   May 22, 2025
8. Sweep generator with marker
   Cor van Rij
   Circuits Oscillators Measurement Diodes NE555
   This circuit is a simple sweep generator. The sawtooth is generated by the PNP transistor and the 555 . The transistor together with the 2 diodes at the base form a constant current source which charges the 330 nF capacitor. If 2/3V CC (=6 V) is ...
   Jan 7, 2025
9. ∆V_BE bread dough incubator
   Stephen Woodward
   Circuits Automation Analogue Design Measurement Diodes AP4310A
   I was surprised recently when a (nearly) two-decade-old design idea of mine for take-back-half temperature control ( Ref. 1 ) got a question from reader John Louis Waugaman. John says he needs a way to control the temperature of batches of rising ...
   Dec 10, 2024
10. Improved PRTD circuit is product of EDN DI teamwork
    Stephen Woodward
    Circuits Measurement Diodes AP4310A
    Recently I published a simple platinum resistance temperature detector (PRTD) design idea ( Reference 1 ) that was largely inspired by a deviously clever earlier DI by Nick Cornford ( Reference 2 ). Remarkable and consistently constructive critical ...
    Oct 10, 2024

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