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  1. AnalogKid

    Minimize Ripple in Rectifier by Waveform, Polarity, Bridge-Type, Inductor, Trafo?

    You want a full-wave output from the rectifiers. This can be done either with a non-center-tapped secondary and a full bridge, or a center-tapped secondary and only two diodes. The latter is slightly more efficient, but a center-tapped transformer (and yours almost certainly will be a custom...
  2. AnalogKid

    Homework

    It could stand to have a little more clarity, but it's a cute little puzzle. C ak
  3. AnalogKid

    Fool-Proof 5V charging circuit design

    Lithium batteries, even small ones, must be charged correctly. This involves both voltage and current monitoring. At your power level, there is no way you can build one for less than you can buy one. ebay is your friend. ak
  4. AnalogKid

    Target Shooting Game: A LED moves back and forth on a strip. Players press a push button to "shoot" when the LED is at a specific target position.

    True, but a non-uC approach covers a variety of digital design concepts. ak
  5. AnalogKid

    Target Shooting Game: A LED moves back and forth on a strip. Players press a push button to "shoot" when the LED is at a specific target position.

    WE NEED for you to show us your work so far; this is not a free homework service. Please post your schematic and parts list. Be sure to have a unique reference designator for each component so we can discuss them individually. Also, include details about the power sources, how fast you want...
  6. AnalogKid

    Alternating L/R 4-way flashers

    SPST - On / Off SPDT - Either / Or ak
  7. AnalogKid

    Alternating L/R 4-way flashers

    I like the #14 approach, but I would move D3 and D4 to the U3 NC contact. Other than that - Doesn't this approach require that the "normal" wiring from the brake and turn circuits to those lights be diode- or relay-isolated? I would prefer diodes, but a 4PDT relay would eliminate all 8...
  8. AnalogKid

    Can an audio amplifier be used to transmit or receive radio signals?

    Your professor was paraphrasing Confucius. CHAP. XVII. The Master said, 'Yu, shall I teach you what knowledge is? When you know a thing, to hold that you know it; and when you do not know a thing, to allow that you do not know it;-- this is knowledge. Confucius (September 28, 551 – 479 BC)...
  9. AnalogKid

    Help with a simple circuit

    If the 12 V bulb also is being powered through the regulator IC, that is 120 mA for the relay coil and 120 mA for the bulb. Increase C1 in the schematic to 1000 uF, and increase the size of the heatsink. ak
  10. AnalogKid

    Help with a simple circuit

    Just a coincidence, the component values in post #2 should be ok for your application. Assuming your AC source is 17 Vrms (as opposed to peak or peak-to-peak), the regulator will dissipate over 1.25 W and should have a small heatsink. ak
  11. AnalogKid

    Voltage regulator driving a pass transistor...

    In the upper schematic it is the voltage between pins 1 and 2 that must be kept below the max spec. With pin 2 at GND, you cannot increase the input voltage above the datasheet spec. In the lower schematic, it is again the pin1-pin2 voltage that is the issue. But because there is a zener...
  12. AnalogKid

    Help with a simple circuit

    Diode bridge > filter capacitor > LM7812 regulator > output capacitor. Circuit is in the datasheet. What is the relay coil resistance / current / power rating? Depending on this, the component values will change. AND the IC might need a heatsink. Here is a typical circuit from the...
  13. AnalogKid

    Schematic question ...

    Again, no. Outside of a teaching environment, a schematic indicates how real components are connected to perform a real function. Each component has a reference designator that is linked to a real Bill Of Materials (BOM), that has component manufacturers and part numbers that have datasheets...
  14. AnalogKid

    Schematic question ...

    No. No. Only for some components and some voltages in some circuits - nothing close to a universal rule. Absolutely no clue what this means. ak
  15. AnalogKid

    A question about "output stages".

    My g.u.e.s.s is that he is referring to a class A, single tube versus a class AB, two-tube push-pull arrangement. A push-pull output stage can be much more efficient, and present a symmetrical and lower output impedance to the load. ak
  16. AnalogKid

    Schematic question ...

    No, it does not. Nope. The term "negative" has specific meanings and applications in electronics, and this one is not correct. A better way to see things is: Positive --- component --- less Positive A direct current does not "become negative" by going through a component, and it is the...
  17. AnalogKid

    Schematic question ...

    No idea what this means. When electrons flow through a diode, that flow creates a voltage differential across the semiconductor junction. For a normal rectifier this is called the diode's "forward voltage", Vf, the voltage across the diode when it is "forward-biased". Thus, the cathode is at...
  18. AnalogKid

    Schematic question ...

    First, that is not a "center-tapped" anything. There is no center tap. It is the simplest possible isolated AC to DC converter. Note that there is no filter capacitor on the output of the bridge, so there will be 100% ripple across the load. The ripple will be unipolar, wo the + and -...
  19. AnalogKid

    Can somebody design me a circuit plan of this gadget (dodos)?

    Why not just buy one? ak
  20. AnalogKid

    Can somebody design me a circuit plan of this gadget (dodos)?

    Link to the product website so we can get some kind of idea of what you are asking about - ? ak
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