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Type: Posts; User: FvM
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Yesterday, 18:41
Thread: Metastabilty and data loss
by FvM- Replies
- 2
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- 146
Closed: Re: Metastabilty and data loss
You should ask yourself what you consider wrong data?
1. Single bit data, toggling at arbitrary times. You'll either read the old or the new data. Both or equally correct, just different.
2. A... -
Yesterday, 16:23
Thread: Connect MQ135 Gas Sensor to Raspberry Pi 3B+
by FvM- Replies
- 4
- Views
- 131
Closed: Re: Connect MQ135 Gas Sensor to Raspberry Pi 3B+
Values read for unconnected (floating) ADC inputs are meaningless. You can either connect known DC voltage for test or just ignore these values. Check the values for ADC0 input connected to sensor.
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Yesterday, 12:45
Thread: Distance between MCU-Phy-Magnetics-RJ45
by FvM- Replies
- 2
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- 146
Closed: Re: Distance between MCU-Phy-Magnetics-RJ45
You have to check impedance matching and termination for each connection. Ethernet is usually terminated at the PHY, in this case, there are no restrictions for PHY to magnetics or magnetics to JJ45...
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Yesterday, 11:15
Thread: How to create a voltage selector circuit
by FvM- Replies
- 6
- Views
- 220
Closed: Re: How to create a voltage selector circuit
The usual solution, also implemented in LM3915 dot matrix mode is working like below:
- have comparators for each threshold level
- have a priority encoder to pass only the output of the most... -
Yesterday, 09:19
Thread: Charging Voltage for a 1.2V NiMH Battery
by FvM- Replies
- 9
- Views
- 268
Closed: Re: Charging Voltage for a 1.2V NiMH Battery
V450HR has a datasheet, it's strongly suggested that you observe the specifications when designing your charging circuit.
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Yesterday, 09:03
Thread: Electrical Length Analysis
by FvM- Replies
- 2
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- 202
Closed: Re: Electrical Length Analysis
A reactive load shifts the resonance frequency, it can't change the electrical length of the resonator itself.
Intuitive explanation, determine equivalent lumped L and C representing the coaxial... -
4th December 2019, 11:31
Thread: Old Altera FPGA EPM7128
by FvM- Replies
- 5
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- 216
Closed: Re: Old Altera FPGA EPM7128
EPM7128S is the obsolete 5V version. Mouser has only one type on stock. If you can switch to pin compatible 3.3V EPM7128A, the series is still in production.
The antique devices are probably a bit... -
3rd December 2019, 23:36
Thread: Wireless rectenna on flexible board
by FvM- Replies
- 8
- Views
- 250
Closed: Re: Wireless rectenna on flexible board
The micro strip trace width may be correct, the trace outside the ground plane is not. You are adding considerable series inductance in the flex design.
Compared to the Johanson reference designs,... -
3rd December 2019, 23:17
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- 20
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- 627
[SOLVED]Closed: Re: PWM applied to load while current limiting on load simultaneously
I'd say, you have partly understood my points. Apparently not yet the point about energetic efficiency.
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To give a simplified example. Assume you get 80% efficiency at 1.5 V... -
3rd December 2019, 23:13
Thread: LM5642 buck converter not work
by FvM- Replies
- 7
- Views
- 348
Closed: Re: LM5642 buck converter not work
Connection of KSx and Ilimx is wrong in your schematic. Probably only a drawing error.
As your measurement shows, the chip is hold in shutdown. May be due to previous OVP or UVP fault. -
3rd December 2019, 22:40
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- 157
Closed: Re: [Moved] CAN Transceiver Chip calculating effective CANH to CANL capacitance
Near. Not C1||C2, it's a series circuit, Cdiff + C1*C2/(C1+C2).
No, Ci and Cdiff values are representing the same physical capacitance. Cpin = Ci + C1 -
3rd December 2019, 17:56
- Replies
- 20
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- 627
[SOLVED]Closed: Re: PWM applied to load while current limiting on load simultaneously
The standard potential of a water electrolysis cell is 1.23V, applying a higher voltage doesn't increase the gas yield per ampere second but causes losses. Practical electrolysis processes operate at...
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3rd December 2019, 16:04
- Replies
- 2
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- 122
Closed: Re: When ad7321 collects voltage, a spike voltage appears
You don't show what's connected to VIN0 and VIN1. The ADC inputs are usually driven by a low impedance buffer, otherwise charge injection of the sampling switches will be observed.
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3rd December 2019, 11:28
Thread: In accuracy in AC Voltage measurement
by FvM- Replies
- 13
- Views
- 395
Closed: Re: In accuracy in AC Voltage measurement
ESP32 maximum ratings suggests that IO pins have clamping diodes, but there's no current rating. For additional safety, you may place external clamping diodes (low leakage schottky or general purpose...
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3rd December 2019, 11:09
- Replies
- 9
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- 380
Closed: Re: is it possible to ZIP a file using STM32F4 ? Any library available?
I was talking about minizip package as zlib addon. It's said to generate *.zip files, but I didn't check myself.
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3rd December 2019, 08:59
Thread: In accuracy in AC Voltage measurement
by FvM- Replies
- 13
- Views
- 395
Closed: Re: In accuracy in AC Voltage measurement
Main problem is Z-diode leakage current. Diode characteristic isn't that steep as you apparently expect. Additionally may be ESP32 input current.
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3rd December 2019, 08:44
- Replies
- 9
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- 380
Closed: Re: is it possible to ZIP a file using STM32F4 ? Any library available?
You didn't review the features of the package, right?
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3rd December 2019, 00:31
Thread: Average vs RMS load-current for LDO design
by FvM- Replies
- 36
- Views
- 626
[SOLVED]Closed: Re: Average vs RMS load-current for LDO design
LDO pass transistor power dissipation is (Vin-Vout)*avg(Iout). Additional considerations for SOA. Irms isn't present in the calculations.
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2nd December 2019, 23:10
- Replies
- 3
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- 205
Closed: Re: Iran Core Transformator No Load Current (Core material)
May be better. For completeness, we would measure current phase angle. Current can be lower due to higher permeability or lower losses.
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2nd December 2019, 22:59
- Replies
- 9
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- 411
Closed: Re: Quartus 19.1 on Ubuntu 18.04 problems with internet and usbblaster
As far I'm aware of, there's no 64-bit code running with Quartus 13 under WinXP. But I didn't check specifically.
USB Blaster driver and JTAG stack components are definitely 32-bit. -
2nd December 2019, 19:49
Thread: Relating Transmitter dBm to uV/m and EIRP
by FvM- Replies
- 8
- Views
- 352
Closed: Re: Relating Transmitter dBm to uV/m and EIRP
FCC measures actual field strength in 3 m distance. If you can prove that your application environment involves a respective attenuation, it should be considered. It would be good to have an antenna...
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2nd December 2019, 19:41
- Replies
- 9
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- 380
Closed: Re: is it possible to ZIP a file using STM32F4 ? Any library available?
O.K. zlib with minizip addition.
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2nd December 2019, 17:41
Thread: Average vs RMS load-current for LDO design
by FvM- Replies
- 36
- Views
- 626
[SOLVED]Closed: Re: Average vs RMS load-current for LDO design
Not for pulsed DC. But that's just theory and doesn't actually matter for the question.
The voltage regulator power dissipation only depends on the average DC current, the circuit must be... -
2nd December 2019, 17:35
- Replies
- 6
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- 220
Closed: Re: VU Meter only with 1LED (PWM) no IC except for OPAMP
According to post #1, you want 4 discrete display levels (duty cycles 0, 0.25, 0.5, 0.75), no continuous variation of duty cycle. If so you need comparators (can be implemented with OPs) after the...
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2nd December 2019, 17:26
Thread: Relating Transmitter dBm to uV/m and EIRP
by FvM- Replies
- 8
- Views
- 352
Closed: Re: Relating Transmitter dBm to uV/m and EIRP
In this case, transmitter power can be increased according to the expectable body attenuation.
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