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    Soil moisture meter , Time domain Reflectometry

    Thansk. For clarity, I dared to redraw it So if I understood correctly, for example Release some PWM1 into the lower probe and sense the ADC1 voltage on C1 on the upper probe If next measurement, I may swap it. Yes? If so I see as the main problem, capacitor C2. This introduces a large...
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    Soil moisture meter , Time domain Reflectometry

    First of all thnaks. After kicking and redrawing it a little more clearly, it's clear to me too. Yes instrumenttion amplifier with amplification controlled by R5 asnd Voltage to Current converter controlled by R20. See new pic With U3B I understand the function, but I don't know how the given...
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    Soil moisture meter , Time domain Reflectometry

    I dug up and disassembled the old soil moisture meter These are two concentric rings made of stainless steel wire, one serving as a transmitting antenna and the other as a receiving antenna. Distance between antennas of the order of 5cm. The output is the voltage corresponding to the soil...
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    From DC TIG inverter to AC and pulse TIG inverter - idea

    Good question . We have a fairly precise inverter On 20A is output voltage 21V On 80A is output voltage 22V Voltage without load does not exceed 50V. At a given switching speed, it is 80V in the entire SOA current range Infineon offers similar transistors for 100V, but RdsOn 2mOhm The...
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    From DC TIG inverter to AC and pulse TIG inverter - idea

    My idea in matter 1IPT012N08N5 input capacitance 13nF, 2pcs paralel 26nF TC4452 is 12A High Speed MOSFET Driver on high side full isolated DC/DC and Digital Isolator SI8620BB. In my opinion, a simple and suitable solution for piece production with 12A excitation MOSFET. The pair of MOSFETs...
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    From DC TIG inverter to AC and pulse TIG inverter - idea

    I have a welding inverter for TIG, in essence it is a switched current source DC 5-160A. An AC inverter is required for aluminum welding, or the polarity of the electrodes must be changed. Expensive inverters also allow pulse welding with adjustable pulse length and frequency, etc. I don't...
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    Transistor flow measuremnt?

    Thank you, I know the principle of ultrasonic anemometers, As long as I developed one, but that would be a different story. It is not suitable for this purpose in terms of both price and size. I need to measure the flow in a tube below 1/2 ", the price can fit in about $ 10 I will return to...
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    Transistor flow measuremnt?

    I'm looking for a way to measure the amount of gas flowing so that it is small and cheap. Gradually I ended up at MAF or Thermo Anemometer. According to my experience, the heated platinum wire has a problem with impurities on its surface, plus I would have to solve how to assign the wire to the...
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    Manganin foil high precise resistor array - homemade?

    I would need 4 very accurate 0.01% and most importantly stable resistors TC 0,2ppm wint high accuracy long life stability.. Such resistances are made, for example, by Vishay and the Z-Foil series . But I would need the resistors to have a very tight thermal relationship . I see the solution in...
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    STM32Fxxx + STM32CubeMX+emWIN from MDK-ARM?

    Anyone using STM32CubeMX with MDK-ARM Pro components? For example I use CubeMX for inicialising STM32F103 and generate project for Keil v5.27 from MDK-ARM I want to add for example graphics library emWIN. MDK-ARM include Manager for Run-Time Environment or I can add emWIN manually or .... In...
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    Gas flow meter + Gas pressure meter + Vacuum meter?

    2. I was looking for a small turbine for gases, but I found them only for liquids I need to measure the argon flow 0-10l / min and air flow 0-100l/min accuracy is not critical 3. The price is decisive. Technically, I need to measure against a reference vacuum. Practically I am interested in...
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    Gas flow meter + Gas pressure meter + Vacuum meter?

    I have an 8mm hose that flows the gas. Gas is Air or CO2 or Agron. Gas pressure is 0-10bar. 1.Pressure Can you recommend a pressure sensor? 0-10bar, Voltage or digital output, resolution min 12bit, to PCB with 4/6mm hose or direct to 1/8" or 1/4" fitting, low price , I do not resist the...
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    Some questions about low side RF routing and interconnection

    In the project I need to lead RF (low tens of MHz) with power up to 100W. PCB is only two side FR4 (price) and have some uncertainties and questions. Device is close in full metal case. 1. Impedance + DC resistance. For my frequency and 1,6mm FR4 is 50Ohm microstrip on about 3mm width of...
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    How to switch feedback networsk in synchronous Step-Down Voltage Regulator?

    I have synchronous Step-Down Voltage Regulator drives by LM76003 500kHz FB have reference voltage 1V. This power supply has power two Independent Load and I wonder how to switch feedback network pro FB input LM76003 if first load not used FB1 have high impedance. The question is how switch...
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    Choice of capacitors to Impedance Matching Network in RF PA?

    I try compare actually available NPO SMD RF capacitors in size 0805 and 1111 Name Size V ESR Q I RMS 251R15S151GV4E 0805 250V 40mOhm 2500 1,5A 100pF at 13MHz VJ1111D151GXLQ 1111 630V 60mOhm 2100 12A 100pF at 20MHz As expected , larger size improved cooling and...
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    Choice of capacitors to Impedance Matching Network in RF PA?

    The possibility of using 5% capacitors and adding a position for another fine tuning capacitor I also considered. Yes, I also think current is the key, so I use 6C in parallel. the problem is, for most conventional SMD ceramics, manufacturers do not provide max current and they are also silent...
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    Choice of capacitors to Impedance Matching Network in RF PA?

    Thank you. The problem is if I want more than 5% accuracy, It is 2% other than RF/Microwave hi Q they are not on mouser.com in offer. And so I still prefer 251R15S151GV4E According to datasheet on frequency under 20MHz 250V, 0803, 2% accuracy ESR around 30mOhm, Q high than 2000 max current...
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    Choice of capacitors to Impedance Matching Network in RF PA?

    I create 150W PA for fixed frequency undrer 20MHz. On output is LC Impedance Matching Network and I need advice on choosing the type of capacitors. L I create on iron powder size T130 induction around hundreds nH. C is around 900pF and my choice is use 7*150pF parallel. Voltage rating min 4xDC...
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    RF Mosfet Class E PA for Dummies or absolute idiots

    Ok that it is an amplifier in class E is just my, perhaps logical reasoning. The whole amplifier looks something like this What class does the amplifier do?
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    RF Mosfet Class E PA for Dummies or absolute idiots

    I have about 100W RF PA with MOSFET about class E, and I would like to understand how such a thing is proposed. I looked into books like this or this frankly, more I understand from this Thing simpler and for beginnings i will ignore everything before G MOSFET see in picture. Frequency of PA...

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