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  1. Hero999

    50V, 50A H-Bridge IC needed

    Here's a schematic, no control circuitry is required assuming the lower MOSFETs are logic level. The diodes prevent both the high and low side MOSFETs from being on simultaniously.
  2. Hero999

    50V, 50A H-Bridge IC needed

    50Hz is fairly low so it should be easy to level shift the h-side P-channel MOSFETs using BJTs and a potential divider or zener to prevent the gate voltage from being exceeded. At higher frequencies this sort of thing gets harder as the resistors slow the switching speed too much. I'll post a...
  3. Hero999

    submerged electronic..need help!

    It depends on the device and whether there's a lot of corrosion on the metal parts or not. Water isn't normally a problem unless it's very salty or the appliance is submerged whilst power is applied. In the electronics  industry, circuit boards are frequently washed with water, it's normally...
  4. Hero999

    I need some help - My first electronics project

    I see what you mean, for speed you need a lot of power because it's exponential i.e. you get diminishing returns; upgrading a car engine from 100hp to 200hp won't double the maximum speed because drag increases with speed. Compensating for different wheel sizes can be done in hardware by using...
  5. Hero999

    50V, 50A H-Bridge IC needed

    50V@30A. I think you'll need to build the h-bridge from scratch from MOSFETs. How fast does it need to switch?
  6. Hero999

    Looking for Simulation software!

    Have you tried LTSpice?
  7. Hero999

    Fm transmitter

    Why don't you just use the circuit from the datasheet? Always read the datasheet very carefully before implementing the circuit. As you've realised, you need a pre-amplifier so why not just look up non-inverting amplifier on Wikipedia and change the resistor values to get the required gain...
  8. Hero999

    Need Help adjusting the hysteresis on my Schmitt trigger with two transistors.

    I don't like that circuit myself, I prefer using a PNP and NPN transistor because the output voltage swing is greater. Look at the circuit where's the positive feedback? Try changing some of the component values. Why not use an IC comparator such as the LM311...
  9. Hero999

    I need some help - My first electronics project

    I'm no expert but it seems like it's way overpowered. The engine isn't the only limiting factor on the car's performance, past a certain point, the transmission, wheels and chassis become limiting factors. If the engine is too powerful for the tyres then it won't be possible to operate it at...
  10. Hero999

    I need some help - My first electronics project

    I don't see why you need to do this, the front and rear wheels should be rotating at the same speed. Surely there are better ways to eliminate wheel spin: traction control four wheel drive?
  11. Hero999

    What is the mean of that? Plz help

    Why don't you ask your supplier? What's the power rating of the motor? Small motors are much less efficient than large motors so if this is an aquarium pump or a small desk fan motor then I wouldn't be surprised. The supplier might have given you the apparent efficiency, i.e VA/Pout rather...
  12. Hero999

    Need Help Buiding the project Linear FM 50Watt with BLY90.

    Don't forget to look at the datasheet for the transistor. http://www.datasheetcatalog.org/datasheet/macom/MRF171A.pdf It's probably designed for use in military radio equipment.
  13. Hero999

    Christmas Light Problem

    Are you sure they're incandescent lamps? They could be LEDs and have a built-in rectifier, does reversing the diode's polarity make any difference? If the lights don't work when the diode is connected in one direction then the lights already have a diode so you need to use a resistor or...
  14. Hero999

    Christmas Light Problem

    Why would it make a difference? The diode only drops 0.7V to 1V. It's the fact that the bulbs only conduct for half a mains cycle that reduces the power dissipation. A diode is also the most economical solution for such a cheap set of lights.
  15. Hero999

    Christmas Light Problem

    Audioguru is right about using a diode, just make sure it's rated for at least 200V. The only trouble with adding a diode it might make the lamps flicker.
  16. Hero999

    Remove the Sell/Buy electronics - Job offer/requests section?

    It always seems to be abused by spammers advertising their cheap Chinese crap rather than genuine hobbyists who want to get rid of their old test equipment or surplus components.
  17. Hero999

    Looking for temperature sensor with +/- 0.5 degree accuracy at 25 degrees.

    Good you came up with a solution. Thanks for returning to tell us about how you did it, most people don't bother.
  18. Hero999

    Christmas Light Problem

    Yes, you need to add a resistor or replace all the bulbs with 8V ones. If you want to use a resistor, you need to know the power/current consumption of the bulbs. The resistor also needs to have a high enough power rating and will probably need a large heat sink. Another option is to power...
  19. Hero999

    where is transducer and transmitter in PCB Board in ultrasonic radar project

    Look closely at the schematic and the PCB; the nodes the traducers are connected to are clearly numbered.
  20. Hero999

    Input and Output impedance

    It depends on what you're driving? If it's a very low impedance load, <600R then use an audio amplifier IC, LM386, TDA2003 etc. for the output stage.
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