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  1. L

    USB Solar Charger Current Question

    Another possibility is related to the MBR150 diode. USB power voltage is specified as between 4.75 and 5.25 volts. However, the forward voltage drop of the diode would be about 0.5 volt @ 500 mA. So the solar charger may only be providing 4.5 volts while the AC adapter may be providing 5.25...
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    A few questions regarding theory.

    Relevant conversion factors: 1 watt-hour = 3,600 Joules 1 food calorie = 4,186 Joules 1 gm sugar = 4 food calories So, 4 watt-hr = 14,400 Joules = 3.44 calories = ~1 gm sugar
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    USB Solar Charger Current Question

    Looking at the datasheet for the V7805-1000 it shows a specified input range of 6.5~32 Vdc and output current of 1000 mA. However, that 1000 mA is not a hard limit since the performance charts are shown for output current over 1000 mA. The more likely source of your problem is the minimum...
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    Can someone reveal me Induction Cooking Circuit

    Zero voltage switching is usually seen in reference to switching power supplies but the same principles would likely apply to high frequency induction oscillators as well. To operate switching power supplies at higher frequencies, which will permit smaller power supplies, transistor switching...
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    best ic ?

    The answer is, "It depends." What is important in your situation? Propagation delay, supply voltage, temperature range, technology, price, availability?
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    MOD 6 counter using 7490

    Doesn't the 7490 have an internal AND gate for the two reset inputs? So why use an external gate?
  7. L

    Calculating capacitance

    When applying the basic capacitance relation C=Q/V just realize that for capacitors in parallel V is the same for all capacitors, and for capacitors in series Q is the same for all capacitors.
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    Help quick please noob question

    Let's say you have a 'box' in which you build your project. Measure the power entering the box (volts x amps). Then measure the power leaving the box. The difference between the power in and power out is the power lost in the box. This lost power is converted into heat within the box...
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    Capacitor Voltage Questions

    Capacitor voltage ratings are not hard limits. A 110 VAC capacitor is not going to fail at 111 VAC. (Ignoring the fact that a 110 VAC capacitor could fail at 110 VAC) The question is how much margin is built into the rating. One company may incorporate a 5% margin whereas another will provide...
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    question about flipflops and decoders

    For the JK from a D flip flop: http://www.play-hookey.com/digital/converting_ff_inputs.html Do the 3-to-8 decoders have Enable inputs? Having four 3-to-8 decoders (4 x 8 =32) and one 2-to-4 decoders (3 + 2 =5) (four=4) should be all that is necessary to suggest wiring a 5-to-32 decoder.
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    LED project for a car

    There seems to be a difficulty with your design specifications. Also, the correct method to deal with overheating is to not overdrive the LED (if it is a low-power LED) and to use a proper heatsink (if it is a high-power LED). Trying to turn off the white LED for the brief periods that the...
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    plz heeeelp : Helmholtz Coils !!?

    You can find a commercial manufacturer of Helmholtz cols and a description of their products at: http://oersted.com/helmholtz_coils_1.shtml http://www.power-guide.com/pdf/Helmholtz-brochure.pdf For calculating the field strength refer to the following pages...
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    ac current sensing circuit design

    If you are sensing current for motor control, might you also be interested in the phase angle between the current and the voltage? Then a non-reactive sensor would be necessary, i.e., one able to sense DC current. In addition to the simple resistor current sensor, Hall effect and...
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    biological signal conditioner

    You might also want to check out the OPA277P instrumentation amplifier. Check out these pages: http://www.microchip.com/forums/tm.aspx?m=114626...
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    Surface Acoustic Wave Touchpanel Project

    What you are looking for are piezoelectric crystals operating as ultrasonic transducers. But you don't want them already mounted in a holder since you will need to mount them directly to the glass substrate. Reflectors are probably just bits of steel or brass glued directly to the glass...
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    Building a pH meter

    Try one that has 20000M ohm input resistance. That will begin to approach the input resistance this pH application requires.
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    correct resistor help

    The formula is R=E/I = (14-2.2)/0.700 = 16.857142
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    need an angle sensor

    For a digital position encoder, see: http://www.qsl.net/oe5jfl/encoder.htm
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    Direction of DC and AC current with diodes.

    When drawing a diode never forget to also draw the diode band which is used to indicate the forward direction of current. Just think of the diode as a switch. When current wants to flow in the forward direction, then the switch is closed. When current wants to flow in the reverse direction...
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    Comparator, 50mV-100mV

    That 4 pF capacitor catches my attention. Even with a relatively high resistance such as 10K the time constant is only just 40 nanoseconds. Yet the response time of the LM339 is 1300 nsec. But if you selected a comparator that was 100 times faster, then you could expect oscillation on the...
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