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  1. HarryA1

    Circuit to increase CEMF spikes

    Using the circuit below with  an 2.5ms wide pulse at 10v  with rise and fall times of 100ns in the simulator I get the wave forms below. The green trace is the input at the base of the mosfet, the yellow trace is the current through one of the coils while the red trace is the voltage across...
  2. HarryA1

    Circuit to increase CEMF spikes

    Looks impressive!  Do you have an idea of the inductance of the coils? I could play with it in the simulator.
  3. HarryA1

    Circuit to increase CEMF spikes

    Is the pulse width large enough for the coil current to reach maximum? I would think current should get to something like (12v - mosfet saturation voltage)/Rcoil.  Also the break down voltage of the mosfet and its diode may come in to play at high voltages? for others:
  4. HarryA1

    Circuit to increase CEMF spikes

    I am not sure about their graph either. You could try  playing around with a capacitor but I am  not sure how much  it affects the voltage drop rate at the output. As you are 95% there why not use an electronic ignition circuit? There are numerous  circuits like this one on the internet. You...
  5. HarryA1

    Circuit to increase CEMF spikes

    Yes, as in the above link.
  6. HarryA1

    Circuit to increase CEMF spikes

    They often use a diode across your R5, I gather to discharge the gate capacitor to speed it up. See this link and click on the "simulate transient" for the IPP60R099CP...
  7. HarryA1

    Help please with this 4017 Kit

    I gather you are using the output from your speaker as input rather than a microphone. In the simulator I get, with zero signal, about 580mv dc at the transistor base and 600mv dc output (pin14). Using 1k sine wave at 10mv as input I get, at the transistor base, a signal between say 670 -...
  8. HarryA1

    Questions about replacing the speaker

    I gather you are employed by Kynix. 🤑 For others: That would be a very large impedance mismatch. The speaker impedance is 4 to 8 ohms while the impedance into the PC is in order of 1k to 20k ohms.
  9. HarryA1

    TDA7498 class D amp could be used as a substitute?

    How do you deal with a SMD that has 36 leads?
  10. HarryA1

    need help electronic/relay problem phone horn

    As you have posted this question on numerous forums I will leave it up to them to answer your question. Good luck.
  11. HarryA1

    Joystick control of two 12 v linear 25 amp linear actuators on a frontend loader.

    These motor controllers may interest you: Motor control Info on Youtube here: Review of control And more info here: More motor control. Reading the reviews/comments will give you more insight. Could one mount  the potentiometers into a joystick control mechanically; some type of gimbal...
  12. HarryA1

    Timer circuit with digital readout

    You may find one of these helpful; you could add LEDs as required: https://www.amazon.com/s?k=Digital+Clock+Kits+Circuit&ref=nb_sb_noss This one shows the circuit diagram,  you make find the manual online for it? DIY timer circuit I like this one the best; try taking that to work.  Fake...
  13. HarryA1

    Newbie Circuit Designer

    "LTspice® is a high performance SPICE simulation software, schematic capture and waveform viewer with enhancements and models for easing the simulation of analog circuits."  There are numerous tutorials and manuals for LTspice online. You can import component models not in its library into it...
  14. HarryA1

    Joystick control of two 12 v linear 25 amp linear actuators on a frontend loader.

    Are you using the type of  actuators that have  brushed motors ?  I gather they have  switches  that limit their travel in each direction. Also I see that folks are building controls using microcomputers like the Arduino but that seems like the hard way of getting one. Are your actuators...
  15. HarryA1

    ESP8266

    ESP8266
  16. HarryA1

    Balanced to double unbalanced converter

    It is very difficult to help someone with home made circuits as there so many things that can go wrong. Like bad components, poor solder joints, miss read schematics, etc. The transformer you are using has two secondary windings of 6 volts rms (8.4 volts peak) each, what are you getting for...
  17. HarryA1

    Flooded NiCad Battery bank Balance circuit (1.2v 32Ah x 20 cells)

    One could use a pair of Arduino mega 2560 microcomputers each has 16 analog inputs. Using two boards each monitoring 10 cells. As each cell is measured relative to ground from the its first  cell the additional voltage would indicate the voltage on that cell, That is if the voltage at the 5th...
  18. HarryA1

    Flooded NiCad Battery bank Balance circuit (1.2v 32Ah x 20 cells)

     In the circuit above the 2SD1805 is an NPN  not a PNP as required. The TL431 is a precision programmable reference.  I could try the circuit in the simulator if I can find a spice model for the TL431 or otherwise simulate it. I see: "The 2SB1205 is a complementary PNP transistor for the...
  19. HarryA1

    Flooded NiCad Battery bank Balance circuit (1.2v 32Ah x 20 cells)

    Tenergy claims to have a Nicd charger for 12 - 24v but I could not find it on their web site. They are less expensive on Amazon.com then on their site.  I would think it less expensive than building one from scratch if it is under 100$.  They require an external power source. I use a Tenergy to...
  20. HarryA1

    power circuit

    Can you use a variac transformer?  This company sells some large ones. See "Variable Transformer Selection Guide" here: https://variac.com/pages/variable_transformers.htm search on 6020-3p for example.
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