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Hot answers tagged low-power

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It may work between 50 Hz and 400 Hz. Over that range your transformer will avoid saturation. If you want it to work down to 1 Hz, you will need to apply a maximum of only 1/50th of your transformer rated voltage to each winding, and can expect to get only 1/50th of the rated voltage out of any winding. A minimum frequency of 10 Hz will mean you must apply ...

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High-brightness LEDs (those with a zillion candela) are noticeable with a tiny current, a fraction of a milliamp... So that could be a good choice. This is thanks to the optics concentrating the light in a tiny cone angle though, which means they lose visibility when you look at them from the side. Make sure they sit against a dark background. If they blink ...

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What are the actual numbers like in terms of power dissipation? Below are a series of diagrams I produced when investigating crystal oscillator power dissipation changes versus external drive resistance (R1) and loading capacitor (CL1 and CL2) changes. The equivalent circuit is a good place to start before jumping into the actual power dissipation: - ...

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Mutual Understanding Obviously, the first step in anything like this is making sure we understand each other. It's usually better if you spend the time needed to communicate well and given what I read from you I thought I might be close enough. But this is where a picture is worth a lot and, next time with something like this, please do consider the idea of ...

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Start with a 5V supply. Series resistor for the LCD backlight. 3.3V regulator (eg. AMS1117-3.3) for the 3.3V rail. Total cost less than a dime. Reminds me of the old adage about asking a barber if you need a haircut. Make sure to follow the recommendations on capacitors for the '1117, especially the output capacitor. The series resistor is the correct way to ...

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It's a known fact that the oscillator needs a minimum (critical) current to start and maintain the oscillation. What are the actual numbers like in terms of power dissipation? Eric Vittoz explains this quite well in his paper about oscillator design. I'll not dive into the technical details but only the result. The critical conductance for the oscillator ...

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<10 pF are common now with high accuracy are preferred for the reasons stated. Then learning how to compensate for Cin and Cgnd stray capacitance are more important. leaving out a gnd underneath reduces stray capacitance to gnd. Generally it is wiser to use an XO rather than an X with caps as the cost is reasonable, or if you prefer accuracy of 1 to 2 ppm ...

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The whole thing needs to generate signals across a frequency range of 1-400Hz. Here's your major stumbling block. At 1 Hz, the transformer's magnetization inductive reactance will be tiny compared to what the transformer normally runs at (circa 50 Hz) and you will get core saturation problems that can only be alleviated by ensuring the AC drive voltage is ...

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Here is an alternate latch circuit based on standard logic gates. R1-C1 form the power-on-reset that forces the circuit into the closed state. A 3 V Kill signal latches the output off by turning off the voltage translation transistor Q1. R3 ensures that the MOSFET is completely off. for a more "firm" turn-off, decrease it to 10K. When the output ...

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