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  1. L

    Converter Circuit

    If the goal is to have 5 amps of current flow from a source voltage of 333 mV (however unusual this may seem), then it is important to consider whether the voltage source is capable of providing that much current at such a low voltage (however unusual this may seem) and what the internal...
  2. L

    current calculation

    It would be more correct to say that the unit of charge flow is the Ampere, and the unit of electrical charge, Q, is the Coulomb. One Ampere is the flow of one Coulomb per second. So 1 Coulomb equals 1 Ampere * 1 second. Current, I, is the flow of charge and is measured in Amperes. Q=I*t
  3. L

    Converter Circuit

    Well, by Ohm's Law R=E/I=0.333/5=0.0666 Is the circuit a demonic resistor with a value of 0.0666 ohms?
  4. L

    Help needed, equivalent resistance of this circuit

    The given resistor network contains an unbalanced Wheatstone Bridge which cannot be solved by simple series/parallel analysis. The following web page, http://www.allaboutcircuits.com/vol_1/chpt_10/3.html, recommends solving the unbalanced bridge using mesh currents and provides an example. As...
  5. L

    Find the MOSFET bias point

    I tried solving for Id algebraically by plugging your source equations into MathCad and ended up with an out-of-memory error on a 64-bit virtual machine that had been allocated 8 GB of RAM. Then tried solving numerically and got a real solution for Id near 0.5 mA, plus two imaginary number...
  6. L

    Time delay assistance

    I would recommend using a 555 timer driving a high-voltage SPDT power switching relay. More likely the 555 timer output will drive a switching transistor and the transistor will drive the relay coil. One relay throw charges the capacitor, the other throw discharges it. Go with the relay for...
  7. L

    Math: Geometric Progression

    I checked my Webster's New World College Dictionary for the meaning of production and it gives the following: "... 2. the rate of producing or amount produced." So if production is increasing, is the rate of producing increasing or is it just the amount produced increasing? It is not clear...
  8. L

    Difference in using OPAMP and TIAOPAMP

    In the attachment I took the node equation for the LPF circuit and derived the transfer function, from that calculated the magnitude vs frequency plot. H(ω) represents the initial component values giving 40 dB of low-pass gain. H1(ω) adds 12 dB gain by lowering the value of R2. H2(ω) adds 12...
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    Difference in using OPAMP and TIAOPAMP

    The TIA datasheet makes the following statement in the section BASIC OPERATION: "The OPA381 is used in inverting configurations, with the noninverting input used as a fixed biasing point." So there is good reason the datasheet doesn't mention anything about the non-inverting mode. The OPA381...
  10. L

    Math: Geometric Progression

    It is not clear whether the old system continues working along with the new system or the new system has replaced the old system. But it does seem that the new system produces 6,000 on the first day, 12,000 on the second day, and 18,000 on the third day. So at the end of two weeks the new...
  11. L

    Math: Geometric Progression

    So if the production increases by 6,000/day, is the production on the first day of the count equal to 3,000 or 6,000 or 9,000?
  12. L

    Calculating gain of an OPAMP

    Here is an example of how to use the GBW product. Suppose there is a simple inverting amplifier with a gain of 20 dB (Rf/Ri=10) and the op amp has a GBW as shown. The inverting amplifier will maintain its 20 dB gain out to the corner frequency of 100 KHz. This is an approximation because the...
  13. L

    How to design a sallenkey highpass filter

    See attachment. Try it yourself.
  14. L

    Help with a circuit....

    The standard method to take a trigger event and extend it for some longer period of time is to use a timer IC configured as a one-shot. Alternatively, the falling of a coin weight could be linked to some Rube Goldberg device involving a see-saw and electro-optical sensor. However, if you would...
  15. L

    Dodgy Power Amp Design

    What if you put a DC bias on the input of IC1b? Many strange things might not happen then.
  16. L

    Another LED-diodes topic

    What effect would you expect from using a different symbol to represent the same component in a schematic? Or by different 'scheme' do you mean the common-anode versus common-cathode configuration? Seven-segment LED displays are sold in both common-cathode and common-anode form, and they are...
  17. L

    Op Amps

    I believe the 7 mV - 11 mV is the calibration voltage for the partial pressure of oxygen in a standard atmosphere. The sensor output voltage will be higher or lower depending on the concentration of oxygen. Also, as an example, the Atmel AT8xEB5114 version of the 80C51 8-bit microcontroller...
  18. L

    Seven segment display decoding

    Here is an example of working through the entire process. There is not single correct optimized solution because the optimization might be to minimize the number of gates, or minimize the number of packages, or take advantage of inputs and their inverse, e.g., from a flip-flop, being available...
  19. L

    Need help with Judge Dredd Lawgiver LED lighting

    You might also look at the CD4015B CMOS Dual 4-Stage Static Shift Register. It has the D-type flip-flops already internally connected as a shift register. You would have to cascade the shift registers on the chip by connecting Q4A to Data-B. This is a fairly simple circuit if you can read and...
  20. L

    Another LED-diodes topic

    The shape of the LED lens does not affect the electrical characteristics of the diode. However, the color of the LED does relate to the forward voltage drop across the diode. To make any sense of the circuit you need to describe the schematic in terms of the LED color associated with each...
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