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Type: Posts; User: Mapuia

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  1. Closed: Another question about Holtek HT12E/HT12D pair

    A couple of weeks ago, I asked a question that involved Holtek's HT12E/HT12D encoder-decoder pair, although the issue was not mainly about them. Now I have a question that's more directly about these...
  2. Closed: Re: Operating four Tx-Rx pairs in close proximity

    I feel really stupid. I completely forgot about the latching nature of the output. My excuse is that I'd been playing recently with a similar encoder-decoder pair - the PT2262/PT2272. The decoder...
  3. Closed: Re: Operating four Tx-Rx pairs in close proximity

    No. At least two transmitters have to be transmitting at the same time. Each transmitter sends one of two possible signals besides the ID address code.

    I thought of using a single common...
  4. Closed: Re: Operating four Tx-Rx pairs in close proximity

    I suspected that, especially with simple OOK signals. Ah well, I suppose I'll have to take another approach. Thanks for the reply.
  5. Closed: Operating four Tx-Rx pairs in close proximity

    I know how to send and receive simple slow code (like on/off signals) using an encoder-decoder combination such as the popular Holtek HT12E/HT12D pair and OOK RF modules like inexpensive 434 MHz...
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    Closed: Re: HDMI-ARC to HDMI audio extractor

    BTW, I'm not asking anyone to guarantee that a particular product - Chinese or otherwise - will or will not work. What I'm asking is about the principle of feeding an ARC signal to a 'normal' HDMI...
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    Closed: HDMI-ARC to HDMI audio extractor

    I hope this is the right section for my question: Will an HDMI-ARC output work with an HDMI audio extractor?

    I bought a 55-inch TV but the built-in sound is quite poor. For watching cable TV, I...
  8. Closed: Keeping a monitor turned on without a signal

    I vaguely recall there being a way to keep a computer monitor from going into standby in the absence of a signal, e.g. for testing purposes. Something like placing a resistor from one of the sync...
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    Closed: Re: Boost converter with higher-than-output input

    Does it mean that the input then goes directly through the diode unregulated, and that Vout will simply be Vin minus the diode drop (ignoring the DCR of L)?
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    Closed: Boost converter with higher-than-output input

    With step-down voltage regulators -linear or switching - I think I have a good idea of what happens when the input voltage drops below the minimum required for proper regulation.

    What happens if...
  11. Closed: Re: Effect of phone charger voltage on charging current?

    Any recommended reading or link(s)? There are many aspects to USB, some of which are not related to power. And though most phone chargers use USB ports nowadays, not all of them do. For example, I...
  12. Closed: Effect of phone charger voltage on charging current?

    How critical is the output voltage of a mobile phone charger in determining the charging current?

    For example, if we were to use a well-regulated power supply as a charger with a low output...
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    Closed: Re: Diode as temperature sensor

    That was my point. Supply from a well-regulated voltage through 22k to 350 Ω dynamic impedance is essentially constant current.


    As I said in my second post, the target temperature regulation is...
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    Closed: Re: Diode as temperature sensor

    Let's do some sample calculations (with some simplifications) and see what we come up with.

    Say we start out at the center temp of 5C. The diode is biased through 22k from 2.5V (TL431). Assume a...
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    Closed: Re: Diode as temperature sensor

    I should have made one thing clear: The circuit is for controlling, not for measuring, temperature. The control range doesn't have to have a linear scale, so variations in forward voltage drop with...
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    Closed: Diode as temperature sensor

    When using an Si PN diode as a temperature sensor, I think it would be best to keep the bias current low in order to minimize self-heating and the effect of the ohmic resistance. Is this correct?
    ...
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    Closed: Re: Problem with ADSL filter

    That could be it. I've already ordered some drum type inductors that wouldn't saturate easily. In the meantime, I'll see if I can scrounge up some old inductors with drum cores of suitable size.
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    Closed: Re: Problem with ADSL filter

    Thanks for your interest. The basic idea behind that circuit is the same as mine. The smaller inductors are intended to spread out the effects of self resonance, but some some filters work without...
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    Closed: Problem with ADSL filter

    I'm having a problem with what I thought would be a simple minor project: A noise filter for a phone-ADSL combo line.

    For some 15 years, I've been using separate landlines for voice calls and for...
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    Closed: Re: SPI transceivers for OOK without MCU?

    No, maybe I didn't express myself clearly. Let me try again. The data I want to send does not conform to SPI or UART standard. The data is hardware-encoded by a dedicated chip like a Holtek HT12E or...
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    Closed: SPI transceivers for OOK without MCU?

    Is it possible to use ready-made 433MHz transceiver modules intended for use with SPI control as simple OOK devices without involving MCUs? I've tried cheap (<$1) Tx-Rx ASK modules and they work well...
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    Closed: Re: What is a 4593 IC?..

    I finally got it. It seems the seller (or whoever provided the image) mixed up the two middle digits. It's 4953, not 4593. After a diligent search for likely candidates, I found a site that shows...
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    Closed: Re: What is a 4593 IC?..

    I haven't bought the board and the image on the ad is not big enough to show the markings on the chips directly. What I cited were notations made by the vendor. Here's the URL:...
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    Closed: What is a 4593 IC?..

    I was looking at an ad for a 32x16 LED matrix board in which one of the images shows the back of the board and identifies the key components. This includes three different ICs - one 74HC245, several...
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    [General]Closed: Advice sought for a beginner.

    How do I start learning about microcontrollers? Which platform do you suggest?

    I can hear experienced regulars and old-timers groaning :) and I don't blame them. These questions must have been...
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