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Type: Posts; User: betwixt

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  1. Closed: Re: Testing Amps on rewound microwave transformer

    If you mean this:
    It isn't correct. The RMS reading of the AC from the transformer will be fine but the DC range will not give an accurate result. It is accurate for steady DC voltages, such as...
  2. Closed: Re: Testing Amps on rewound microwave transformer

    What exactly are you trying to measure?
    You cannot measure the 'Amps' because that is what you take FROM the transformer, not what it will just give to you. However, if you intend to draw 'X' Amps...
  3. Closed: Re: Testing Amps on rewound microwave transformer

    Provided you have enough capability to provide the maximum current you need, that is true. Amps represent the load, all you have to do is make sure the source is capable of producing them safely.
    ...
  4. Closed: Re: Testing Amps on rewound microwave transformer

    You are not understanding how current ratings work.
    Firstly, take note of what FvM wrote in post #3, it will work but that kind of transformer is not optimal.

    A transformer produces voltage, not...
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    Closed: Re: load sensing circuit/relay

    In principle your design will work but it has some drawbacks, there is an easier way!

    The problems are that you drop some of the line voltage in the transformer primary and the voltage reaching...
  6. Closed: Re: Regulating temperature of mains connected heating element: Skipping mains half cy

    This is getting rather complicated and expensive. My initial thoughts if burst control is to be used is a triac fired with a ZCD opto-coupler, in turn fed from a comparator with the setting control...
  7. Closed: Re: Regulating temperature of mains connected heating element: Skipping mains half cy

    The offset would only occur on the start of a conduction cycle, if you use SCR/Triac switching it will turn itself off accurately anyway.

    Why use back-to-back power FETs when a triac is so much...
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    Closed: Re: Project using Opamps-intermediate level

    The inverters (NME0505 etc.) take DC in and produce DC out, they are very small, about 10mm x 15mm x 6mm and have four pins. The two output pins are electrically isolated from the two input pins. If...
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    Closed: Re: very simple and short inverter circuit

    It is your video so you should know!

    In truth, yes it will work but it will be very inefficient and the LED lamp will not light at full brightness.

    First problem: Stepping the voltage up by 145...
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    Closed: Re: Repair SMPS for cooktop

    It uses voltage monitoring and linear feedback.

    The principle is to convert the output voltage to a current through the opto-coupler LED. It could be done with a simple series resistor but it...
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    Closed: Re: Project using Opamps-intermediate level

    The easiest way to produce a FIXED negative supply is to use a commercial inverter module. There are many with 5V in and 5V out or with 12V in and 12V out. As the output is isolated from the input,...
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    Closed: Re: Repair SMPS for cooktop

    Without knowing the specification of the original opto it's difficult to know if your replacement was suitable. They are however, very reliable. Typically they degrade in CTR over long periods but...
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    [SOLVED]Closed: Re: BLE v5 dongle isn't working on Ubuntu

    The advert says it will not enumerate in HID mode, perhaps that is the problem. You might have to 're-flash' it with more suitable code for your application.

    If lsusb shows it as a CP210x device...
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    Closed: Re: Project using Opamps-intermediate level

    Simply use two potentiometers, both wired across 0V and supply. That way you have two independent variable voltages with only two components being used!

    Do be careful with the supply voltage for...
  15. Closed: Re: 80m phase shift SSB transceiver, How does it detect USB/LSB?

    I think it is DSB so no switching is needed.

    Brian.
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    Closed: Re: How can we send multiple bytes via UART?

    A UART can only send one byte at a time, some have a FIFO buffer that allows more than one byte to be queued for sending but the general principle is to load the first byte then monitor for the UART...
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    Closed: Re: The magical audio filter other opamps?

    I agree, and it will work better than a 741.
    The caveat with NE5532 and NE5534 devices is they have head-to-toe parallel diodes across the inverting and non-inverting inputs. That isn't a problem...
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    Closed: Re: Project using Opamps-intermediate level

    Suggestion: an analog calculator. One or two voltage inputs and one voltage output.

    You could implement add, subtract, multiply, divide and possibly log and square root functions by using op-amps...
  19. Closed: Re: Bootstrapping board for programming the ESP32

    I have attached the schematic for the ESP32 dev board. If you move the parts in the "Micro USB 5V&USB-UART" box to your bootstrap board and make connections of GND, TXD, RXD, EN and IO0 to your main...
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    Closed: Re: XMEGA UART TO RS485 problem

    RS485 uses only two wires and has a protocol for deciding which direction the bus information is traveling, it also specifies how devices in parallel on the bus are addressed so only one device at a...
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    Closed: Re: XMEGA UART TO RS485 problem

    You haven't enabled the MAX489!
    Tie '/RE' to ground and 'DE' to 5V to enable the receiver and transmitter circuits. You should ideally add a resistor of about 120 Ohm across the receiving end of...
  22. Closed: Re: HKTS 220 Power Supply board troubleshooting

    It could be. To be honest it is difficult to tell whether capacitors are working unless you monitor for residual signal across them. A good capacitor will charge on peaks of current and discharge on...
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    Closed: Re: Multi-loop antenna selector

    I didn't check accurately and you may be right but it is rather complicated and don't forget that regulators usually pass lower input voltages to some degree even if it is below the voltage needed to...
  24. Closed: Re: HKTS 220 Power Supply board troubleshooting

    Capacitors are the most likely cause. All the other parts have long lives but capacitors start to degrade from the day they are made, even if not used although if they are in use they degrade...
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    Closed: Re: Multi-loop antenna selector

    I wouldn't recommend that as a solution, it will work sequentially but not exclusively. It will add more loops as the voltage increases rather than allow individual selection. There would also be no...
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