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fokhan_96 wrote:Sooo the time on my car deck run fast by about 2 mins every month. Does this mean something wrong with my car.
Duane 3NE 2NR wrote:
Rovin wrote:well i must be d only man who never bothered to ever set clock on my mw & stove ...
MG Man wrote:Not sure how to check this 20 minute thing. Help pls
Sōsuke Aizen wrote:MG Man wrote:Not sure how to check this 20 minute thing. Help pls
You sickening
maj. tom wrote:adnj wrote:Sorry but that is referencing an analog clock circuit.maj. tom wrote:The 50/60 Hz in EU/SA is apparently an extremely important thing in Utility Frequency and they use atomic clocks to sync it exactly because it is used in any and everything with a microchip that controls time signals. Including the railways.
All digital circuits have a DC supply. DC is necessary to latch the transistors in the logic circuits. AC supplies are rectified and stepped down typically to the 1.0V to 24V range which is then provided to the board.
hmm ok, i understand. A microchip would generate a clock frequency using a piezo-crystal or an oscillator circuit using pure DC. I was thinking that a timer IC would use a dedicated half wave rectified signal waveform to generate pulses and then perform calculations on the function for an output at the required frequency. like this diagram:
https://www.electronics-tutorials.ws/po ... ation.html
Thanks for clearing that up.
Duane 3NE 2NR wrote:“Most digital clocks in microwaves are frequency based. North America is on a 60 cycle frequency, it keeps time based on that, if the frequency of the AC increases, the clock will run faster, and if the frequency decreases, it will run slower. Are you on "shore power" or "generator power" ? Depending on the input frequency, the microwave clock will either be accurate (60 Hz), fast (>60Hz) or slow (<60Hz)”
maj. tom wrote:maj. tom wrote:adnj wrote:Sorry but that is referencing an analog clock circuit.maj. tom wrote:The 50/60 Hz in EU/SA is apparently an extremely important thing in Utility Frequency and they use atomic clocks to sync it exactly because it is used in any and everything with a microchip that controls time signals. Including the railways.
All digital circuits have a DC supply. DC is necessary to latch the transistors in the logic circuits. AC supplies are rectified and stepped down typically to the 1.0V to 24V range which is then provided to the board.
hmm ok, i understand. A microchip would generate a clock frequency using a piezo-crystal or an oscillator circuit using pure DC. I was thinking that a timer IC would use a dedicated half wave rectified signal waveform to generate pulses and then perform calculations on the function for an output at the required frequency. like this diagram:
https://www.electronics-tutorials.ws/po ... ation.html
Thanks for clearing that up.
So I was kind of half-way correct in my assumption btw. Been looking though some service manuals. This design is quite common in kitchen appliances. Not all appliances rely on an internal clock piezo crystal, they in fact do sync with commercial power AC frequency. Because it's cheaper, and because the application does not require precise timekeeping.
These are descriptions from several microwave oven service manuals on what the control circuit does and how it acquires the timing signal from a rectified AC signal. As in my diagram above.
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In one service manual I even found an entire description with diagrams of how this synchronous circuit generates the timing signal from the AC frequency supply.Duane 3NE 2NR wrote:“Most digital clocks in microwaves are frequency based. North America is on a 60 cycle frequency, it keeps time based on that, if the frequency of the AC increases, the clock will run faster, and if the frequency decreases, it will run slower. Are you on "shore power" or "generator power" ? Depending on the input frequency, the microwave clock will either be accurate (60 Hz), fast (>60Hz) or slow (<60Hz)”
So just to re-bump this topic, yes this explanation is correct. TTEC... well the power generation company really... has been sending a wonky 60 Hz frequency signal to the nation. Any devices not synced to a network and that relies on this AC frequency is not going to be accurate time at all.
DMan7 wrote:fokhan_96 wrote:Sooo the time on my car deck run fast by about 2 mins every month. Does this mean something wrong with my car.
Well yuh know what to do...
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Yup, I would set the correct time on both and after a few days I realize that both are 5 minutes faster.Duane 3NE 2NR wrote:The microwave and stove clock still runs fast every so often.
I assume other people still experiencing this also?
Duane 3NE 2NR wrote:The microwave and stove clock still runs fast every so often.
I assume other people still experiencing this also?
Rovin wrote:well i must be d only man who never bothered to ever set clock on my mw & stove ...
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