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  1. AnalogKid

    Trigger Pulse for IC555 using Inverted Square Pulse

    If the voltage sensor output is a low impedance that swings below 0.4 V in its low state, then Q1 is the buffer stage. If the low output is closer to 1 V, add a 1N914 or 1N4148 diode in series with the Q1 base. ak
  2. AnalogKid

    Best AC to DC Converters

    25 kHz switching frequency and no pedigree - makes me nervous. 13 cents per watt in ones - pass. ak
  3. AnalogKid

    How to increase current in a circuit

    Both of the parts you had links to are non-isolated boost DC/DC converters. Basically, the circuit is one storage inductor and two switches. The input switch connects the inductor to the input to charge it up. Yes, you can charge up an inductor very much like you charge up a capacitor, except...
  4. AnalogKid

    How to increase current in a circuit

    No. You are confusing increasing the output current *capability* of a low power device with an amplifier (the 555 circuit), with increasing the output current available from an energy source (like a boost converter). Here is how to estimate the relationship between input current and output...
  5. AnalogKid

    need a switch that will deactivate with man overboard

    On many speedboats with an ignition switch there is a pull-tab dead man switch near it. Insert tab, ignition switch works. Remove tab, engine dies. For some unknown reason, the same thing is built into my snow blower. Buy or build something similar, and tie the tab to your butt with string. ak
  6. AnalogKid

    What diode is used in this schematic?

    J3 pin 2 is connected to the regulator output, but is labeled GND. ak
  7. AnalogKid

    12VDC Switch Controller - Adjust Timer

    To be clear, Colin is saying to increase the value of the capacitors one at a time to see which one affects the timing. But you want a 2000% increase, and that is almost certainly not possible with whatever circuit this thing has. You might have to connect this device to an external...
  8. AnalogKid

    Power Supply Questions

    A good starting point is one AC/DC supply for whichever voltage requires the most *power*, and converting the other two voltages from that. But everything changes if most of the power is going to the 5 V because boosting is less efficient and more expensive than bucking. Depending on what the...
  9. AnalogKid

    Trigger Pulse for IC555 using Inverted Square Pulse

    C1 is the power supply decoupling capacitor for the 555 IC. In my library the power pins are not shown on common parts. The circuit in post #41 requires that the sensor circuit output be able to source and sink less than 1.5 mA. If it can sink 1.5 mA with an output voltage less than 1.0 V...
  10. AnalogKid

    Trigger Pulse for IC555 using Inverted Square Pulse

    Just poking the bear...
  11. AnalogKid

    Trigger Pulse for IC555 using Inverted Square Pulse

    Attached is a circuit that does everything you have described, and uses a 555. Notice that there is no buffer stage. That is because nothing that you have described requires one. ak
  12. AnalogKid

    Trigger Pulse for IC555 using Inverted Square Pulse

    Cluck cluck ...
  13. AnalogKid

    Trigger Pulse for IC555 using Inverted Square Pulse

    1. A CD4093 is an IC. An LMC555 is an IC. Why is one allowed and the other not allowed? 2. After the bridge rectifier, is there a filter capacitor to smooth the fullwave rectified AC into a DC voltage? Then what, a zener diode and an optocoupler, or something more precise like an analog...
  14. AnalogKid

    Trigger Pulse for IC555 using Inverted Square Pulse

    No and no. My bad. I rarely use the internal gate for the monostable output, but I didn't have an inverter for the normal output. Fingers got ahead of brain. Add 1 transistor inverter to U2C pin 8. Another solution is to add an RC differentiator to U2D pin 13, but then it's just like a 555...
  15. AnalogKid

    Trigger Pulse for IC555 using Inverted Square Pulse

    This should do what you describe. Because C2 is so large, diode D1 is added to protect the U2C inputs. With every sensor input pulse, FET-A is the width of the sensor pulse, and FET-B turns on the instant FET-A turns off. This circuit uses a true monostable - the output pulse runs it's full...
  16. AnalogKid

    Trigger Pulse for IC555 using Inverted Square Pulse

    Let's try this again. Varun: The first stage is a voltage sensing stage. It's output is such that if the Input voltage is above 60% of 230V.. we get a positive 12V DC as output but if lesser than 60% then we get a 0V DC Output thus creating a Square Wave. ak: Does this mean that the sensor...
  17. AnalogKid

    Trigger Pulse for IC555 using Inverted Square Pulse

    Who knows. With each explanation, the problem gets worse, not better. Now there is a 5-second delay somewhere. Or pulse width, or whatever. The early posts described FET-B being turned on after FET-A, and showed a pulse former and a 555 monostable, so that's what id whipped up (with...
  18. AnalogKid

    Best AC to DC Converters

    I've used other models in the LS series. Excellent, reliable supplies, plus the Lambda pedigree. ak
  19. AnalogKid

    Current Measurement Rating

    You are combining two different specifications of the meter incorrectly. The 10 A rating is the maximum current the meter can sense without damage when acting as a current meter. The 1000V rating is the maximum voltage the meter can sense without damage when acting as a volt meter. The meter...
  20. AnalogKid

    Trigger Pulse for IC555 using Inverted Square Pulse

    What is the reason for the inverter before the trigger pulse generator in your schematic? A 555 is triggered with a negative edge, which is the trailing edge of the signal out of the buffer stage before the inverter. ak
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