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  1. L

    Removing a passive crossover from an amp

    While I'm not much of an audiophile I believe that the purpose of a crossover is to separate a signal frequency range to better match the frequency response of the speakers used. So is your third power amp meant to drive a sub-woofer? Can your other speakers handle the full frequency range...
  2. L

    Determine no. of '1's in a 4-bit input

    FYI: It takes five 2-input NAND gates to make one 2-input XOR gate.
  3. L

    Mouth Light

    Recommend that before you put much work into a mouth mount, get a battery & LED combination that will provide sufficient lumens and operating time to be acceptable. My guess would be that a CR2032 battery would power a 20 mA LED but not a 1-watt LED that needs 300 mA. Also, a white LED needs...
  4. L

    Determine no. of '1's in a 4-bit input

    What if you did a K-map in stages? For example, do a map for A & B, then another one for C & D, then combine those outputs together into another map.
  5. L

    Mouth Light

    Recommend you experiment with super-bright white 1-watt LEDs. For a power source, maybe a small lithium battery such as a CR123A. Or consider using a flesh-core transformer with the primary as a necklace and the secondary coil in the mouth under the tongue. Choose a frequency equal to that...
  6. L

    Multiplying Voltages?

    Is your intent to design a circuit around a core multiplier chip such as the MPY534, or try to duplicate the circuitry within multiplier chip itself?
  7. L

    X Y sensor interpretation

    Suppose one were to perform an A-D conversion of the voltage on each photocell. How often must the position be updated? Let's guess 20 times per second. That allows 50 msec to scan 100 photocells and do the analog to digital conversions, giving 500 usec to complete each individual cell scan...
  8. L

    Quick Question-Noob

    The MCP6002 seems to have the same 1 pA input bias current as the specified op amps, so that should not be a problem. Resistor R9 (actually the ratio of R7 & R8 to R9) controls both the AC & DC gain together. I don't understand the purpose of resistors R5 & R6. The AC gain at high frequency...
  9. L

    Quick Question-Noob

    Question: Are your op amps the same MAX4257 as specified in the application note? If not, it could explain the large output offset. Input leakage around the sensor input circuit may also be a culprit. Cleanliness is next to good insulation in high impedance circuits such as this. R9, the...
  10. L

    Log-Log graphs

    Taking the logs would give you a log-log data series that you could plot on graph paper. No need for log-scribed graph paper here. A log-log plot of the given equation would be a straight line. From the straight line you can get a slope and intercept. The slope and intercept provide the K...
  11. L

    what exactly is Voltage

    I would hope that what is clear is you will never find the answer you seek. Asking the question, "What is voltage?", is almost the same as asking, "What is gravity?" Nobody knows the answer to that one either. Gravity is an observed natural phenomenon relating force and the attraction...
  12. L

    what exactly is Voltage

    The question "What is voltage?" seems more appropriate for a physics forum than it is for electronics. So I dug out my old physics textbook (Sears & Zemansky, 1947) and found the relevant answer. But first one must understand the concepts of electric potential and electromotive force. The...
  13. L

    Identifying objects with a single point of contact?

    Have you thought about covering the floating objects with a surface contact transfer antenna formed from a matrix of capacitively coupled active elements. Each object will use the surface antenna in a multiplexed fashion to continuously transmit its own ID, then listen for contact signal IDs...
  14. L

    ArchitecturalModel Dilemma..

    Regarding the parallel path to ground, instead of a 'glitch' try to think of it as a 'feature'. Since the center limit switch breaks the ground connection at the center position, the house would sit in the center forever unless a brief ground contact is provided to 'kick' the house off center...
  15. L

    ArchitecturalModel Dilemma..

    Here is a simple relay circuit that may fulfil your needs; if there is something wrong with the design, I just can't see it. Note that I have shown the rocker switch as pushbuttons operating DPDT relays. It would also be possible to fabricate a lever operating two DPDT pushbutton switches...
  16. L

    Phasor transformation

    I arrived at the same expression for L as you did so you seem to be on the right track.
  17. L

    basic electronics (or is it?) --> carnival project

    What sort of 'randomness' are you looking for? There are a number of possibilities: TRULY RANDOM: The state of each lamp is independent. Each lamp has its own random generator, such as a noise diode & comparator & latch circuit. A 555 timer would periodically clock all the latch circuits...
  18. L

    Count to three

    What you want to do is quite simple in logic design, however the most difficult part of this design will likely be in the electrical control interface to the air ram. Do you have the specifications for the control interface? Voltage, current, pulse duration, de-bouncing? Why would the other...
  19. L

    Driving opamp output to near ground?

    Check more closely. The Electrical Specifications heading clearly states that VSS=GND and VL=VDD/2.
  20. L

    Driving opamp output to near ground?

    With a 25 KΩ load resistance the output current will be 100 μA and the specified headroom is 100 mV. Yet Figure 2-20 in the datasheet is a plot of output headroom versus current showing an output voltage of less than 10 mV with output current at 0.1 mA. Why the difference? The 100 mV is...
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