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  1. (*steve*)

    Hi folks! I'm new here and don't understand JFETs

    Not to self: do not stay in the same hotel as @BobK
  2. (*steve*)

    What do you reckon the most produced component is?

    Capacitor. There is capacitance between every combination of two components.
  3. (*steve*)

    What do you reckon the most produced component is?

    The answer is clearly "any component in a MELF package". For every one you use, several roll of onto the floor, never to be seen again.
  4. (*steve*)

    Ramping voltage to current converter?

    Vin is shown as being connected to R5 and being with respect to ground. What you need between your op amp that produces a voltage varying between 0.4V and 1V is a voltage adder . This must add -0.4V so the voltage swing will be from 0V to 0.6V. Google non inverting summing amplifier and...
  5. (*steve*)

    Ramping voltage to current converter?

    The circuit you show is not a voltage to current circuit, and operates open loop so it's not very accurate or stable over temperature, load, and line variations. Look here. The sense resistor in this case is 50Ω which will have 1V across it at 20mA. In your case you want 1A at 0.6V, so change...
  6. (*steve*)

    Accuracy Component Tester.

    The point is @caps is that you are not using a transistor tester, you are using a general purpose component tester. The things you're testing now have nothing to do with testing transistors. Measuring various resistors is not exactly thrilling reading when there seems to be no point to it. If...
  7. (*steve*)

    SMD identification?

    It looks like a Fuji Electric FA5502M Google that and you'll find datasheets and suppliers in abundance.
  8. (*steve*)

    Accuracy Component Tester.

    Exactly. We haven't seen any measurements you'd typically associate with a transistor. But I know these devices do them. Of what they test, I'm not sure you need any particular level of accuracy. Even if you want to find closely matched devices, all you need is something which produces...
  9. (*steve*)

    Ramping voltage to current converter?

    Harald's suggestion will point you in the right direction. You have 2 things to do. One is to create a variable current source that will carry between 0 and 1A for a voltage varying between 0V and 0.6V (a 0.6Ω current sense resistor may be useful here). The other is to scale the input...
  10. (*steve*)

    Accuracy Component Tester.

    Resistance :-?
  11. (*steve*)

    Can this smarphone works without a (possible) protection diode?

    Yes, it just looks like a regular diode. If find something in the same package that can handle (say) 1A. Fortunately the image of the intact board is good enough to see the markings which indicate the cathode.
  12. (*steve*)

    i need someone to look at this circuit before my teacher will get it

    Your circuit may be fine, but let's tidy it up. Drawing things in a standard way assists readability. Firstly, eliminate crossing lines where they're not necessary: Next, make sure that identifiers are not obscured by lines running through them: Move isolated parts of the circuit away...
  13. (*steve*)

    Accuracy Component Tester.

    Why? My picoammeter is around a couple of percent accurate. It works fine. I think you misunderstand what accuracy means.
  14. (*steve*)

    New idea for oscillator

    Oh, wait, wait. Lmgtfy!
  15. (*steve*)

    Ramping voltage to current converter?

    Compare your ramped voltage to the voltage across a resistor in series with the device. The op amp will cause the current to be proportional to the input voltage, and the choice of resistor allows you to determine what the ratio is.
  16. (*steve*)

    New idea for oscillator

    Yep, that's a crazy idea. It might be worth investigating what an oscillator actually is.
  17. (*steve*)

    555 timer

    Almost certainly not (sorry). OK, a 555 is capable of this, but the resulting circuit will be unreliable. For the time constants you're talking about, the input current of the 555 and the leakage current of the capacitor will likely interact to prevent the capacitor from ever reaching the...
  18. (*steve*)

    2 layer and 4 layer pcb

    2 layer will also be substantially cheaper than 4 layer. Settle on a track width that you will normally use -- say 0.8mm and stick to that unless you need thicker traces for high currents or finer traces to fit between pads etc. Thinner traces increase the likelihood of broken traces, although...
  19. (*steve*)

    Pulse swwitching and circuits

    1/f
  20. (*steve*)

    How are all our colleagues in Florida?

    Bugger. That's no laughing matter.
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