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  1. Kiwi Bruv

    Mosfet Latching

    I have built a simple PWM drive with a 555 and an op amp. The op amp drives a trans which drives a mosfet. However the mosfet seems to be latching. The mosfet is conducting, with no gate signal present, a test bulb lights brightly. When I apply the PWM to the gate the bulb dims as it should...
  2. Kiwi Bruv

    Electric assist bike

    Hi, I am building an electric assist bike and need some help with the concept as I don't know much about motors. It will be a 300W 24V DC motor, driven by PWM with a microcontroller helping. I want the level of assist to be dependant on the rider - not have it pre-set by setting the motor...
  3. Kiwi Bruv

    PWM

    I am building an electric bike. I am going to build a PWM circuit using a 555 chip to generate the PWM signal and and MOSFET to switch the motor power supply. I will drive it using a variable resistor initially and later a Picaxe microcontroller so I can do some fancy stuff. My motor is 300W...
  4. Kiwi Bruv

    Buried wire detector

    After 3 mnths of experimenting with my wire following robot project I've cracked the sensor. This is no small achievement for me. Now I need some more help. I have an astable 555 driving an approx 100hz signal into a wire with about 80 mA @ 12V. My inductor is picking this up, I've used this...
  5. Kiwi Bruv

    newb transistor question

    I have an npn transistor set up as a switch driving an LED. If everything is connected to the 5v dc supply it works fine. But I want it to switch a 12v supply using a 5v microcontroller output. If I connect everything to the 12 v supply it works great to. But when the base is controlled by the...
  6. Kiwi Bruv

    Buried wire detector

    Hi have basic electronics knowledge. I am building a robot that I want to stay confined in an area outside on the lawn. I want to bury a wire in the ground and use a detector on the robot to keep it within the boundary. I know induction is probably how the thing will work but I have no...
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