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  1. crutschow

    Slow down AC fan speed

    An AC TRIAC lamp dimmer will reduce the fan speed, but introduce harmonics and often generates a buzz in the motor. I am presently using a high-voltage capacitor in series with a fan to quietly lower its speed and the power it consumes. Try a 1µF or more non-polarized (film type) 400V...
  2. crutschow

    Current Flow

    Yes, when the transistor is on, the base-emitter voltage of a silicon transistor is about 0.7V. Since the LED requires more voltage than that to turn on, it will not conduct any current and will look like an open circuit.
  3. crutschow

    Opamp + capacitor gain circuit

    Since there is no path for the op amp input bias current, the output will likely go to one of the supply rails and stay there. The capacitor will have no other effect on the circuit response, even if you did provide a DC path.
  4. crutschow

    Oscilloscope always showing Sine Wave

    How do you expect us to know what is wrong, when you give us no info on the oscilloscope you have?
  5. crutschow

    Resetting Latching Relay with Momentary Button

    Okay, Just wanted to clarify, as that might not be obvious to the TS.
  6. crutschow

    Question about op amp dual supply circuit...

    That can be difficult to prevent. One way is to use an analog switch to not connect the output to the load, until the circuit has settled to it's quiescent condition.
  7. crutschow

    Quality Pot for Servo

    That and ignoring any large outlier (spike) voltages when you do the average.
  8. crutschow

    Resetting Latching Relay with Momentary Button

    That works if the relay is a single-coil latching type.
  9. crutschow

    Quality Pot for Servo

    The Pot output can be noisy when it is being rotated. What is the pot resistance? How fast is the pot moving? What is the voltage on the pot? What is the load on the pot output? Can you filter the pot output to reduce the noise?
  10. crutschow

    Resetting Latching Relay with Momentary Button

    Not really. If you answer our questions and tell us exactly what you want to power with this circuit, then we can better suggest a circuit for your needs.
  11. crutschow

    Resetting Latching Relay with Momentary Button

    Didn't know this was for production, as my circuit was not particularly designed for minimum production cost The relay is a significant cost and will depend upon the load. Does it have to be a relay controlling the load? How many do you expect to sell?
  12. crutschow

    Resetting Latching Relay with Momentary Button

    Below is the LTspice simulation of a circuit, that should do what you want: It uses a MOSFET (M1) to power the relay coil from the R2-C1 momentarily gate signal when the +12V is applied (blue trace) until the relay pulls in and is latched by the ground connection through one of the relay's NO...
  13. crutschow

    Resetting Latching Relay with Momentary Button

    0.3a/h is a battery rating, not a device load rating. How much current does the load require?
  14. crutschow

    Resetting Latching Relay with Momentary Button

    Not enough info. How is the relay set? What is the relay contact load voltage and voltage, and AC or DC? What is relay coil voltage, and AC or DC?
  15. crutschow

    Output voltage higher than expected

    Welcome to the Brain Flatulence Society. I'm a member in good standing. ;)
  16. crutschow

    Output voltage higher than expected

    Not exactly. It's a common emitter-follower series regulator controlled by a shunt Zener diode reference. It has no feedback from the output so has poor regulation.
  17. crutschow

    Protection of my loads (batteries + equipment) from alternator

    If you really want over-voltage protection then you could use an SCR crowbar circuit, that shorts the alternator output and blows the fuse you have added (or opens an added breaker) if the voltage exceeds a preset value. I can post such a circuit if you are interested in building one. At what...
  18. crutschow

    555 monostable on power delay

    Then reduce it to 1kΩ or less. How fast do you want the recovery time to be? Why does it need to be fast?
  19. crutschow

    555 monostable on power delay

    Likely the bridge supply comes up more slowly then connecting it to the DC supply so the TR signal doesn't say low, long enough. Try increasing the value of C1 to 10µF or greater (and/or increasing the value of R3).
  20. crutschow

    JFET "Amplifier". How Would This Work?

    Could it be an AM or FM modulated oscillator?
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