Search results

Search Forums New Posts
  1. Alec_t

    Analyse output from laptop charger

    If you have both chargers then comparing their outputs with a scope could be informative. You could perhaps also use a dummy load to test output voltage as a function of load current; but not beyond ~3A or so unless you are feeling brave and are certain that the "3.65A" rating is for continuous...
  2. Alec_t

    Using PWM to regulate power dissipation

    Why do you have the 100uF cap on the input to the bridge?
  3. Alec_t

    Driving MOSFET with IR2104

    Sounds like the SD pin isn't at logic high, the chip suffered from having -5V on its input, or else the bootstrap isn't working. Have you tried adding a load to the output?
  4. Alec_t

    Clueless Noob - A/C to DC switch

    What speed does the turntable run at as it is now? My guess is the turntable already has a built-in speed regulator. It might be possible to tap into that to give a choice of speeds.
  5. Alec_t

    Hello from Wales UK

    Croeso!
  6. Alec_t

    PANASONIC KX-TG2570 - 2.4 GHz Cordless Answering System - My handset display says "Out of Range"

    Does the manual tell you what 13 beeps signifies?
  7. Alec_t

    design buck converter with arduino controlling pwm

    I doubt that KrisBlueNZ can help you; he passed away. :(. What load do you have connected to the output? If there is nothing to pull the source of the FET down then the bootstrap won't work properly.
  8. Alec_t

    uC controlled DC-to-AC inverter

    So, with R1-R4 all equal 1kΩ you're getting about 100mA of shoot-through current. With the Amp'sR3 = 220Ω that reduces to ~9mA. Ideally you should reconfigure the bridge and its driver circuits so that Q1-Q4 have a 'dead time' in which it is ensured that Q1 and Q3 can't possibly be 'on' at the...
  9. Alec_t

    oticon streamer battery replacement

    Do you have room for a battery of different dimensions? Slightly thicker batteries with a 3.7V 400mAh rating and fitted with a JST connector are advertised.
  10. Alec_t

    Fuzz Pedal Problems.

    Simulation shows that the circuit makes a good attenuator rather thn a fuzz generator :). How did you arrive at the component values?
  11. Alec_t

    uC controlled DC-to-AC inverter

    That's the right place. With the resistors R1-R4 all equal 1k, the load disconnected and PinA at 'logic high', you should see a non-zero (<1V) voltage when the meter +ve probe is on the V+ point and the meter -ve probe is on the Q1 emitter.
  12. Alec_t

    new to electronics. need help understanding a circuit

    Welcome to EP! This is NOT a project for someone new to electronics. The slightest error could be FATAL.
  13. Alec_t

    simple Calculator

    By chemical processing, e.g. of oil.
  14. Alec_t

    simple Calculator

    By studying programming languages.
  15. Alec_t

    Fuzz Pedal Problems.

    Some values for the components shown would be useful ;).
  16. Alec_t

    uC controlled DC-to-AC inverter

    Both Q1 and Q3 will be ON when PinA is high. Both Q2 and Q4 will be ON when PinB is high. Connect a low-value resistor (e.g. 1 Ohm) in series with Q1 emitter and use the scope to monitor the voltage across it. When PinA is high the monitored voltage will be non-zero because of the shoot-through.
  17. Alec_t

    uC controlled DC-to-AC inverter

    Your amps A and B act primarily as level-shifters. The collector resistors R3 in amps A and B prevent the bases of Q1 and Q2 in the H-bridge from being pulled up to V+. As a result, both Q1 and Q3 (likewise Q2 and Q4) conduct simultaneously, causing shoot-through.
  18. Alec_t

    12v 18650 power bank and a DC jack Trouble

    In my experience the middle pin is generally +ve, but there are exceptions.
  19. Alec_t

    how to get certificate registered

    Take it to a registrar.
  20. Alec_t

    Advice on modding/designing/building guitar pedal

    It does connect to something; a ground plane (the pink area). If you look closely there are short tracks going north, south, east and west from the mounting hole.
Top