Circuits & Schematics: Design - 2

11. 1 A, 20V PWM DAC current source with tracking preregulator
    Stephen Woodward
    Circuits Supply Microchip MIC2253
    .. design idea reprises another “1 A, 20 V, PWM controlled current source” ( Ref. 1 ). Like the earlier ...
    Mar 4, 2025

12. Design an RTD interface with a spreadsheet
    Robert S. Villanucci
    Circuits Analogue Design Measurement Analog Devices AD633 OP177
    .. the system is to achieve a high level of precision. One way to obviate the nonlinear characteristic of an RTD sensor is to design analog hardware to perform the curve-fitting mathematics before any additional signal processing occurs. This ...
    Feb 25, 2025

13. A precision digital rheostat
    Stephen Woodward
    Circuits Analogue Design Supply Microchip MCP4131
    .. tolerance. These limitations conspire to make Dpots a difficult medium for implementing precision rheostats. Recent EDN design idea (DI) articles have addressed these issues with a variety of strategies and topologies: Op-amp wipes out ...
    Feb 25, 2025
14. Tracking preregulator boosts efficiency of PWM power DAC
    Stephen Woodward
    Circuits Supply Fairchild LM317 2N3906
    .. design idea revisits another: “PWM power DAC incorporates an LM317” ( Ref. 1 ). Like the earlier ...
    Feb 17, 2025
15. 1-A, 20-V, PWM-controlled current source
    Stephen Woodward
    Circuits Supply ON Semiconductor LM337
    .. design idea (DI) takes an unusual path to a power-handling DAC by merging an upside-down LM337 regulator with a ...
    Feb 7, 2025
16. Metal detector uses single IC
    Rachel Hageman Steve Hageman
    Circuits Measurement National Semiconductor LM389
    .. input capacitors, or approximately 2 nF) of the Q 1 oscillator determine the frequency of the search oscillator. In this design, the frequency is approximately 370 kHz. For years, this frequency has prevailed in metal detectors, because ...
    Feb 5, 2025
17. How to collect free energy from atmosphere
    Swagatam Majumdar
    Circuits Bad Prescriptions Supply
    .. µF/25 V electrolytic Improving the free energy device The following more comprehensive free energy deriving circuit design was forwarded to me by one of interested readers of this blog Mr. Prashanth Dhonde (Figure 2). Figure 2. ...
    Jan 15, 2025
18. PWM power DAC incorporates an LM317
    Stephen Woodward
    Circuits Supply Fairchild LM317
    .. of the conventional approach of backing up a DAC with an amplifier to boost output, this design idea charts a less traveled by path to power. It integrates an LM317 positive regulator with a simple 8-bit ...
    Jan 14, 2025
19. Capture 16-bit readings of 8 thermistors in less than 1 second for $2
    Stephen Woodward
    Circuits Measurement Signal Processing, Filters Texas Instruments CD74HC4051 CD74HC4053
    .. uncomplicated, inexpensive, and fairly fast (1 MHz), low power voltage to frequency converter (VFC) “Voltage inverter design idea transmogrifies into a 1 MHz VFC” ( Ref. 2 ). See Figure 2. Figure 2. Modified voltage inverter ...
    Jan 14, 2025
20. An ultra low distortion oscillator with THD below -140 dB
    Vojtech Janásek
    Circuits Oscillators Measurement National Semiconductor LME49710
    .. 3 , R 4 , C 1 , C 2 , and C 3 , forms a band-pass filter that sets the oscillator’s resonant frequency to 2 kHz. The design uses a Wien bridge with values R, C, R/2, and 2C because it the oscillator needs an inverting gain of 1. ...
    Jan 10, 2025

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