Circuits & Schematics: -Wire Barometer 5/10 Volt Design vrs - 3

21. Current converter performs purely on paltry phantom power
    Stephen Woodward
    Circuits Measurement Supply Texas Instruments OPA2244
    .. 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 the grand ...
    Jul 23, 2026

22. Eight solar cell lithium-ion battery charger
    David A. Johnson
    Circuits Supply Solar Texas Instruments TLV2401 LMC7111
    .. behavior. Note that at one full standard sun intensity, only about 70% of the peak current is available at the needed 0.525 volt point. However, as a lithium ion battery reaches the target 4.2 volts, the charge current naturally tapers off, ...
    .. Figure 5. 2.2 amp-hour lithium-ion battery. Figure 6. 4.9 amp-hour lithium-ion battery. Version 2 Jim Wilber looked at my design for a battery charger and sent me some suggested changes. He suggested using the LTC4412 ideal diode IC to ...
    Jul 16, 2026
23. Isolated remote switch circuit
    David A. Johnson
    Circuits Supply Toshiba TC4S584F,LF
    .. and can be positioned 1000 feet away. The circuit uses a custom ferrite toroid type transformer. About 20 turns of magnet wire forms the primary winding and 10 turns forms the secondary winding. A simple Schmitt trigger oscillator drives ...
    Jul 15, 2026
24. Tachometer frequency to 4-20mA loop current converter
    Jayapal Ramalingam
    Circuits Measurement Texas Instruments LM2907
    .. input is grounded. A detailed description of a loop current converter with governing equations can be found in my earlier Design Idea “A 0-20 mA source current to 4-20 mA loop current converter” ( Ref. 1 ). As a bonus, this ...
    Jul 8, 2026
25. Position sensor gets linear 4 to 20mA current source output
    Stephen Woodward
    Circuits Measurement Texas Instruments SN74HC4066 TLV197-Q1 TLV9051
    .. tolerant, linear 4 to 20 mA, current mode output. Figure 3. Dangling the TLV431 shunt voltage reference Z1 from the 15 volt supply is a shortcut toward implementing a noise- and cable length- tolerant current mode output. Here’s ...
    .. 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 ...
    Jul 8, 2026
26. Capacitive position sensor with linearized output
    Stephen Woodward
    Circuits Measurement Texas Instruments SN74HC4066 TLV9051
    .. 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 capacitive position sensors ( ...
    Jun 25, 2026
27. A pot of many colors
    Nick Cornford
    Circuits Analogue Design Microchip MCP6002
    .. pair to drive not just two but three LEDs. As everyone knows, rainbows always have pots of gold at their ends. This Design Idea reverses that, starting with a pot (no gold, alas) and ending with a rainbow. Bi-color LEDs can be ...
    Jun 24, 2026
28. 4-20mA to 0-20mA converter sips mere microamps
    Stephen Woodward
    Circuits Analogue Design Interfaces Diodes AP4310A
    .. like TO220 packaged power pass transistors sporting substantial heatsinks. Would Greta T. approve? I think not!7 The design in Figure 1 offers a cool (and maybe even useful) efficiency improvement. It thriftily recycles most of the 4 ...
    Jun 23, 2026
29. 4mA-20mA to 0mA-20mA converter's current mirror drives grounded load
    Stephen Woodward
    Circuits Analogue Design Interfaces Texas Instruments TLV197-Q1 TLV431
    .. V REF input of Z1. The principle in play is discussed here ( Ref. 1 ). A potentially annoying shortcoming of the Figure 1 design, however, is its current sink output that’s referred not to ground but to the V+ source node, which ...
    Jun 15, 2026
30. Dual-fan PWM cooling circuit with a 6W isolated flyback power supply
    Hesam Moshiri
    Circuits Supply Microcontrollers Usage Atmel ATtiny13
    .. project presents the design and implementation of a dual-fan PWM cooling circuit, integrating a compact and efficient power supply with ...
    Jun 15, 2026

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