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Posts posted by HarryA

  1. It takes in the order of 200ms for the current to reach maximum in the simulator. The current through one coil is about 1.18 amperes. The voltage across the coils is about 200kv - you better wear rubber boots! Perhaps the simulator got carried away.

    There is an equation: time = inductance/resistance = 63% of the charge. So t= 0.380h /10 ohms would give 38ms. That would give 0.74amps at 48ms (38ms + 10ms pulse on delay) in the second waveform. That seems about right; at the white dot.



  2. 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 the coils.  I will try increasing the pulse width until the current reaches steady state and see what is looks like and post it later.

    I do not understand the current.




  3. 16 hours ago, Kerrowman said:

    So is the graph label ’Power Loss’ the back EMF at the drain? 

    And do you think any capacitance across the gate resistor would help?

    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 could get up to a few thousand volts then!1320123097_Car-Coil-1schemetic.png.208d110655708293d77166fa574bf990.png

  4. 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.


    I wonder if the turn off delay of the 555 propagates through the circuit? The 555 off time is 2us compared to the equivalent timer 1455 at 100ns.


  5. 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 - 690mv, At the output pin14 0 to 3.5v.circuit.png.72babfa8d681e307e5ff59721de33bcf.png

     Using a 2SC2412K in the simulator which I believe is similar to the 9014.


  6. 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 mount?  Adding push button switches to the control to reverse directions would be doable I think.  There maybe game type  joystick controls that have them already built in?

  7. "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 using other spice models.

    see:  https://www.analog.com/en/design-center/design-tools-and-calculators/ltspice-simulator.html

    A circuit in LTspice:


  8. 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 similar to this one?  https://www.amazon.com/dp/B079G1NZHT/ref=emc_b_5_t?th=1

    also look at these: https://www.progressiveautomations.com/collections/control-boxes? I gather their 30 amp dual controllers are only 15 amps each.  They have joysticks here:


    This is like what you have  now? https://www.amazon.com/Forward-Reverse-Module-Actuator-Reversing/dp/B0881N7F4M/ref=sr_1_53?crid=25CETHKMKA6N1&keywords=linear%2Bactuator%2Bcontroller%2B12v&qid=1637517171&s=industrial&sprefix=Linear%2BActuator%2BController%2Cindustrial%2C232&sr=1-53&th=1


  9. 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 cell where  say 6.5v to ground and the 6th cell where 7.9v the computer would "know" that cell  is at 1.4v and thus charged. It would switch it out of the circuit and replace it with a shunt resistor.  

    Also there are Arduino devices to monitor current up to 5 amperes using a Hall effect device.

  10.  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 2SD1805."

    Characteristics of 2SB1205 Transistor

    • Type: PNP
    • Collector-Emitter Voltage: -20 V
    • Collector-Base Voltage: -25 V
    • Emitter-Base Voltage: -5 V
    • Collector Current: -5 A
    • Collector Dissipation: 10 W
    • DC Current Gain (hfe😞 100 to 400
  11. 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 charge my quadcopter's battery.

    As you are fabricating you own battery you could set it to charge say 10 cells at a time but that requires 8 charges; mine will do 15 cells.

    see: https://power.tenergy.com/chargers/for-battery-packs/12v-24v-nimh-nicd/

  12. If it works in another unit why do you think it is damaged? Perhaps the fault lies with the error sensing circuit.  A  fault that arises with vacuum cleaner power heads is that a string, etc.  gets wound around the wheel axis impeding the wheel. There are videos related to this type of problem on youtube: for example see: https://www.youtube.com/watch?v=kqq6Ezilky4

    In regard to the mosfet; if there is a voltage at the gate of 3 to 4 volts or more the voltage across the mosfet should be less the supply voltage. If not that may mean the mosfet is opened - not conduction current.

    If I were to build a robot I would buy one to use as a base;

    https://shopgoodwill.com/categories/listing?st=robotic cleaner&sg=&c=&s=&lp=0&hp=999999&sbn=&spo=false&snpo=false&socs=false&sd=false&sca=false&caed=11%2F17%2F2021&cadb=7&scs=false&sis=false&col=1&p=1&ps=40&desc=false&ss=0&UseBuyerPrefs=true&sus=false&cln=1&catIds=&pn=&wc=false&mci=false&hmt=false




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