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  1. (*steve*)

    Unknown voltage of a Op amp

    oh, it would be worth answering LvW's question as im sure he can provide a lot more assistance suited to your existing level of knowledge.
  2. (*steve*)

    Unknown voltage of a Op amp

    true, and in this case the bias current is zero, and you have correctly calculated the voltage drop across it must be zero. So if the voltage (with respect to ground) at one end of the resistor is 100mV, what is the voltage at the other end (I.e. At the noninverting input of the op amp)? And...
  3. (*steve*)

    Differential Amplifier - Differential Mode

    look at the circuit with that question in mind. perhaps you could consider the minimum current through either Rc and the output voltage in that case. As the current through Rc increases what happens to the output voltage? What effect would a low vs high value resistor have? the answer to this...
  4. (*steve*)

    Switch activated by Amps

    I later thought of a low temperature thermal switch after uncovering some 85C devices as I was cleaning up. Here is an example: https://www.rockby.com.au/catresultssQL_12.cfm?Searchkey=thermal+switch&stock_no=26833 This isn't a good price, and I might try to get something with a lower...
  5. (*steve*)

    Differential Amplifier - Differential Mode

    is there a minimum and maximum current through Rc?
  6. (*steve*)

    Pot for throttle control

    even with a simple pot, you could also wire in a momentary contact switch that would require you to hold it to enable the motor. make sure the controls are weatherproofed!
  7. (*steve*)

    2 leg 2.1mm DC socket use in a circuit.

    yeah, you must use an appropriate voltage or better an appropriate charger.
  8. (*steve*)

    Cheap source for ATTINY85 SOP

    is there less than 5 seconds remaining on the auction? If not I wouldn't be bidding yet.
  9. (*steve*)

    Common Base

    Two voltages mean one voltage difference does it not?
  10. (*steve*)

    Simple Motor Controller Circuit

    And it's often a dissipation issue as well. The voltage across the body diode is generally higher than the voltage across the mosfet when it's switched on. However, if you're looking at very short transient currents, heating is not likely to be an issue.
  11. (*steve*)

    Question about current

    Things have really gone downhill since the 1960's haven't they ;-)
  12. (*steve*)

    Unknown voltage of a Op amp

    Dig some more. Why do you think V+ is 0V? You've already said no current flows through the resistor R1. In that case, what can you say about the voltage at each end? Look at post 18. That's telling you the voltage across the resistor, not the voltage at any particular point.
  13. (*steve*)

    Unknown voltage of a Op amp

    Be careful with what you say. "Voltage" and "Voltage drop" are two different things.
  14. (*steve*)

    Question about current

    Well, there are DC clamp ammeters, but they're pretty exotic compared to the normal AC clamp ammeters. If an AC clamp ammeter was connected to a wire carrying DC it may show a very low current if there is some ripple as this is a measurable AC component on top of a large and unmeasurable DC...
  15. (*steve*)

    Unknown voltage of a Op amp

    Possibly, but what does the equation say the voltage drop across the resistor will be?
  16. (*steve*)

    Simple Motor Controller Circuit

    Body diodes tend to have very poor reverse recovery and are suitable only at low frequencies. As long as you're not switching at high speed (i.e. for PWM control) it's not a huge problem.
  17. (*steve*)

    Unknown voltage of a Op amp

    Reconsider this in light of V = IR
  18. (*steve*)

    Cheap source for ATTINY85 SOP

    Digikey will sell them to you for $USD0.725 if you purchase 6000 of them, otherwise here are the price breaks. Your price seems to be an ebay price from China. If you don't mind DIL versions, check out the auctions for 10. They are trending a little lower.
  19. (*steve*)

    2 leg 2.1mm DC socket use in a circuit.

    Assuming you place the power socket before any power switch then yes, that will work. You need to be careful because this socket always has the battery voltage across it. You really don't want to short it out.
  20. (*steve*)

    Unknown voltage of a Op amp

    What is the input current for a theoretically perfect op-amp?
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