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🤖Запрошуємо на відкриту лекцію "АІ: тренди та виклики"

Новини - 1 година 13 хв тому
🤖Запрошуємо на відкриту лекцію "АІ: тренди та виклики"
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kpi чт, 04/23/2026 - 16:05
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Відкрита лекція від Huawei Україна, за участі МОН, КПІ ім. Ігоря Сікорського та експертів галузі Штучний інтелект у 360°: від архітектури мереж та стратегії цифрової освіти до реальних кейсів протидії діпфейкам.

Linearly variable two-wire loop current generator

EDN Network - 2 години 19 хв тому

Circuits such as the design described here implement useful tools for a diversity of calibration and testing applications.

A two-wire loop current generator is a useful tool for the testing, calibration and commissioning of current-to-pressure (I/P) converters connected with control valves, actuators, etc. in process industries. Such product can also help calibrate the analog input modules of distributed control systems (DCSs) and programmable logic controllers (PLCs) by simulating process signals.

Wow the engineering world with your unique design: Design Ideas Submission Guide

In these and other applications, it is advantageous to generate a loop current which is linearly variable for precisely setting the desired current. A Design Idea published in EDN’s December 10, 2025 issue, although compact and otherwise excellent, does not support linearly variable current, since the output current relationship is Io=1.24/R1. R1 is adjusted to vary the output current, but since it is in the denominator of the equation, the resultant current variation is not linear.

Figure 1 describes a circuit where the variation of loop current is linear. Here, the loop current is directly proportional to the voltage set by potentiometer RV1. Moreover, this current can service a source or sink load up to 500 ohms without need for recalibration. These two requirements are essential for a loop current generator in process industries.


Figure 1 With this linearly adjustable two-wire current source, RV1 is adjusted to set the current, and either LOAD1 (source) or LOAD2 (sink) can be connected.

How does the circuit work? First connect a 24V DC supply, a DC ammeter and a load resistor—say, 200 ohms—at the source or sink side. In field applications, this portion is built into the I/P converter, DCS or PLC.

Two currents exist at pin 3 of U1A :

  • I span=Vset/R5
  • Through R4=(Io*R6)/(R4+R6)

The first current minus the second current = 0, as U1A is an operational amplifier.

Io is the loop current. Hence Vset/R5= (Io*R6)/(R4+R6). After rearranging, Io= (Vset/R5) * (1+R4/R6). Substituting the values, R4/R6= 99. Hence, Io= (Vset/R5)*100.

Thus, Io is directly proportional to Vset which is adjustable linearly by RV1. A multiturn potentiometer selected for RV1 will enable smooth and precise adjustment.

Other comments, in closing:

  • U3 generates 5V DC.
  • Q1 and U1A adjust the loop current Io proportional to Vset.
  • R1 and Q2 set the current limit for Io at approximately 30 mA for safety reasons.
  • The loop current is settable from 0.5 mA to 23.5 mA, which is sufficient for this application.
  • For different current settings, select R3, R2 and R5 as per the equation given earlier for Io.
  • And Q1 requires a heat sink.

Jayapal Ramalingam has over three decades of experience in designing electronics systems for power & process industries and is presently a freelance automation consultant.

Related Content

The post Linearly variable two-wire loop current generator appeared first on EDN.

CSA Catapult issues annual report for 2024–25

Semiconductor today - 5 годин 24 хв тому
The UK’s Compound Semiconductor Applications (CSA) Catapult has published its Annual Report for 24–25, highlighting the impact and value brought to the economy...

AXT closes public offering, raising $550m

Semiconductor today - 5 годин 37 хв тому
AXT Inc of Fremont, CA, USA — which makes gallium arsenide (GaAs), indium phosphide (InP) and germanium (Ge) substrates and raw materials at plants in China — has closed its underwritten public offering of 8,560,311 shares of common stock at $64.25 per share. The firm received total gross proceeds of about $550m, before deducting the underwriting discounts and commissions and other offering expenses...

The system architect’s sketchbook: The pickleball protocol

EDN Network - 6 годин 8 хв тому

Deepak Shankar, founder of Mirabilis Design and developer of VisualSim Architect platform for chip and system designs, has created this cartoon for electronics design engineers.

The post The system architect’s sketchbook: The pickleball protocol appeared first on EDN.

The ASIC design remake in the AI era

EDN Network - 7 годин 40 хв тому

The traditional ASIC design model—focusing on relatively stable standards and well-defined functions—is now under pressure. That’s partly because AI workloads are highly diverse, compute-intensive, and tightly coupled to software behavior and system context. Consequently, ASICs, besides being application-specific, are now increasingly becoming system-specific.

Take the case of a custom chip for LLM inference, where the prefill and decode stages are now running on separate chips. So, there are two ASICs instead of one: the compute-intensive part of the application (prefill) and the memory-bandwidth-limited part of the application (decode). That shows how ASICs are increasingly becoming modular and disaggregated with cross-domain collaboration spanning architecture, packaging, and manufacturing.

Read the full article at EDN’s sister publication, EE Times.

The post The ASIC design remake in the AI era appeared first on EDN.

Power electronics market to grow at 10% CAGR to over $65bn by 2036

Semiconductor today - Срд, 04/22/2026 - 23:03
OEMs across power electronics applications are demanding increased efficiency and power density for power electronics components, while also insisting on solid reliability and device miniaturization. To enable this, wide-bandgap (WBG) semiconductors silicon carbide (SiC) and gallium nitride (GaN) are being adopted across the power electronics market. These WBG power semiconductors support higher-voltage operation and new power architectures across data centers, electric vehicles (EVs) and renewables...

Wolfspeed appoints Tokyo-based regional president for Asia Pacific

Semiconductor today - Срд, 04/22/2026 - 22:17
Wolfspeed Inc of Durham, NC, USA — which makes silicon carbide (SiC) materials and power semiconductor devices — has appointed Yasuhisa Harita as regional president for Asia Pacific, effective 1 June. He will be based in Tokyo and lead Wolfspeed’s commercial strategy across Japan, Korea and the ASEAN (Association of Southeast Asian Nations) region, with responsibility for driving revenue growth, enhancing strategic customer relationships, and executing the company’s regional commercial and operational objectives...

The system architect’s sketchbook: GenZLens built in a dorm

EDN Network - Срд, 04/22/2026 - 17:40

Deepak Shankar, founder of Mirabilis Design and developer of VisualSim Architect platform for chip and system designs, has created this cartoon for electronics design engineers.

The post The system architect’s sketchbook: GenZLens built in a dorm appeared first on EDN.

У КПІ відбувся традиційний турнір з волейболу імені Михайла Павловського

Новини - Срд, 04/22/2026 - 17:02
У КПІ відбувся традиційний турнір з волейболу імені Михайла Павловського
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kpi ср, 04/22/2026 - 17:02
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🏐 Всеукраїнський турнір з волейболу імені Михайла Павловського організували Профком КПІ ім. Ігоря Сікорського спільно з Асоціацією ветеранів волейболу України.

Конференція «Чорнобильська катастрофа: медичні, екологічні та соціальні наслідки через 40 років»

Новини - Срд, 04/22/2026 - 16:50
Конференція «Чорнобильська катастрофа: медичні, екологічні та соціальні наслідки через 40 років»
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kpi ср, 04/22/2026 - 16:50
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КПІ ім. Ігоря Сікорського став майданчиком Всеукраїнської наукової конференції «Чорнобильська катастрофа: медичні, екологічні та соціальні наслідки через 40 років» — одного з ключових заходів, які університет організував у памʼять про трагедію Чорнобиля.

Аспірант КПІ на Міжнародному конкурсі з фізики

Новини - Срд, 04/22/2026 - 16:44
Аспірант КПІ на Міжнародному конкурсі з фізики
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kpi ср, 04/22/2026 - 16:44
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Редріх Путятін, аспірант кафедри технічних та програмних засобів автоматизації ФАПІЕ КПІ ім. Ігоря Сікорського, показав хороший результат на Міжнародному конкурсі з фізики The International Physics Competition (IPhyC).

My Purpose-built Hashboard Repair Lab – Workbench Wednesday

Reddit:Electronics - Срд, 04/22/2026 - 15:47
My Purpose-built Hashboard Repair Lab – Workbench Wednesday

Happy workbench Wednesday! I’ve been itching to post this since last Thursday haha.

I’m Abacus of FooseyRhode and I specialize in repair of a specific type of computer part called an ASIC Hashboard, and those PCBs are what this setup is built around servicing.

Honorable mentions at my desk that might catch some curiosity

  1. The Overhead Cable Trays.

  2. The rail mounted, Digital Microscope.

  3. The Heatgun Glory Hole.

  4. Soldering Iron suspended by pulleys.

  5. The Quad-table-top fans (Fan Deck).

1 and 2.) The overhead cable trays are super helpful for the obvious, but also for storing some accessories out of the way.

My primary heatgun for example. With it up there, wrist strain from the heavy heatgun gun hose is practically eliminated.

I also mounted my PC and digital microscope up there. Microscope benefits because table vibrations are gone, and computer is just there for cable management.

3.) See image 3. Looks crazy but it’s very necessary for my work. The PCB I work on are typically single layer PCB secured to a giant aluminum plate. A lone heatgun is not capable of achieving solder flow, and hot plates are extremely impractical for PCB like this. Thus, I apply heat from above, and below.

Getting the damn thing mounted safely was the hardest part. I used a pneumatic vesa monitor mount, but backwards. I hammered the vesa mount into shape and secured it to a desk beam. Then I secured the opposite end of the mount to the heatgun.

4.) The pulleys just keep the soldering iron cable out of my way. Honestly, I’m just resolving a minor inconvenience for myself with this.

5.) My 3D printed Fan Deck! It’s four 120mm fans powered through a potentiometer so I can control the speed. It’s used primarily when I am diagnosing a board.

The boards I work on use around 40-90 amps when operating, but for diagnostic, require only 10-20 amps to test properly. Point being, they heat up very rapidly, and heat affects my diagnostic. The Fan Deck is a means to cool boards down while simultaneously injecting power into them.

submitted by /u/FooseyRhode
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CVD Equipment demonstrates single-crystal SiC boule growth in collaboration with Stony Brook

Semiconductor today - Срд, 04/22/2026 - 15:06
CVD Equipment Corp (CVDE) of Central Islip, NY, USA (a designer and maker of chemical vapor deposition, thermal processing, physical vapor transport, gas and chemical delivery control systems, and other equipment and process solutions for developing and manufacturing materials and coatings) has announced the successful growth of single-crystal silicon carbide (SiC) boules grown on CVDE physical vapor transport (PVT) systems and characterized by Stony Brook University (SBU) in support of their new ‘onsemi Research Center for Wide Bandgap Materials’...

BJT is accurate sensor for absolute temperature in Kelvin and Rankine

EDN Network - Срд, 04/22/2026 - 15:00

Simple math implemented in a (very) simple circuit. What’s not to like?

A very cool (also warm!) property of the base-emitter junction of (most) small signal BJTs is the ΔVbe temperature-sensing effect.  ΔVbe temperature measurement is aptly described and applied here by famed and forever remembered analog design guru Jim Williams (see page 7):

At room temperature, the Vbe junction diode shifts 59.16mV per decade of current. The temperature dependence of this constant is 0.33%/°C, or 198μV/°C. This ΔVbe versus current relationship holds, regardless of the Vbe diode’s absolute value.

Wow the engineering world with your unique design: Design Ideas Submission Guide

Rearranging Williams’ math, since 198uV=1V/5050, 198μV/°C per current decade works out to (the easier to remember…ha!) ΔVbe/°C = Log10(Current-ratio)/5050.  So, if we need any given ΔVbe/°C, the required

Current-ratio = 10^(5050 ΔVbe/°C).

For example, for ΔVbe/°C = 100uV, Current-ratio = 10^(5050 * 100uV) = 10^(0.5050) = 3.20

Of course, this trick also works for Fahrenheit, albeit with a different scale factor.  Since 1 °F = 5/9 of 1°C, for Fahrenheit the corresponding Current-ratio = 10^(9090 ΔVbe/°F).  Therefore, for the 100uV example, if ΔVbe/°F = 100uV, then Current-ratio = 10^(9090 * 100uV) = 10^(0.9090) = 8.11

Figure 1 shows this simple math implemented in a (very) simple circuit:


Figure 1
An ordinary BJT Q1 makes an accurate absolute temperature sensor in two different units (K and R).

Here’s how it works. Switch U1a applies alternating current ratio drive to sensor Q1 per Williams’ method.  The ratio is (approximately) Current-ratio = (1/R1 + 1/R2)/(1/R2) = (R2/R1 + 1) = 3.20 for measurement in units of Celsius (Kelvin) and = 8.11 for Fahrenheit (Rankine).  The “approximately” thing comes in because the resistor ratio needed to be fudged (slightly) to compensate for the few 10s of mV of varying difference between V+ and Q1’s Vbe and thus make the current ratios accurately equal to the calculated values.

The resulting 100uVpp per degree AC signal is synchronously rectified by U1b and filtered by C3 to become the 100uV per degree of absolute temperature DC output signal suitable for direct input to a DMM.  A ~5kHz clock signal for current switching and rectification is provided by U1c, with a little help from one side of U1a.

Note that, per Williams’ analysis of the ΔVbe effect, accuracy of temperature measurement relies only on the accuracy of the current ratio and therefore on only the precision of R1 and R2.  No other reference is required or relevant and any 2N3904 will do. 

The V+ supply, for example, can vary from 3 to 6 volts without affecting accuracy.  Passive output impedance is roughly 10k.  So, loading by a typical 10M DMM input won’t either.

Thanks, Jim!

Stephen Woodward‘s relationship with EDN’s DI column goes back quite a long way. Over 200 submissions have been accepted since his first contribution back in 1974.  They have included best Design Idea of the year in 1974 and 2001.

Related Content 

The post BJT is accurate sensor for absolute temperature in Kelvin and Rankine appeared first on EDN.

Bosch sampling third-generation SiC chips to global automakers

Semiconductor today - Срд, 04/22/2026 - 12:19
Germany-based Bosch Group has started to introduce third-generation silicon carbide (SiC) chips and is supplying samples to global automakers...

Bosch sampling third-generation SiC chips to global automakers

Semiconductor today - Срд, 04/22/2026 - 12:19
Germany-based Bosch Group has started to introduce third-generation silicon carbide (SiC) chips and is supplying samples to global automakers...

Квест "Святкуємо число Пі" в ДПМ

Новини - Срд, 04/22/2026 - 11:50
Квест "Святкуємо число Пі" в ДПМ
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Інформація КП ср, 04/22/2026 - 11:50
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Державний політехнічний музей імені Бориса Патона при КПІ ім. Ігоря Сікорського підготував і провів у межах Родинної суботи до Міжнародного дня числа Пі, який щорічно відзначається 14 квітня, квест "Святкуємо число Пі". Програму квесту спільно розробили два відділи музею – науково-освітньої та експозиційної роботи.

TU Delft’s Karen Dowling receives NWO Open Competition ENW-XS grant

Semiconductor today - Срд, 04/22/2026 - 11:48
Dr Karen Dowling of the Microelectronics Department in the Faculty of Electrical Engineering, Mathematics and Computer Science at TU Delft (Delft Univrsity of Technology) has been awarded an NWO Open Competition ENW-XS grant for her research on materials that can be used in space exploration at extreme temperatures. Specifically, she will investigate the thermoelectric properties of gallium nitride by modelling, fabricating and testing it at temperatures ranging from 500K to 4K...

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