Search results

Search Forums New Posts
  1. polyal

    2.4v NICAD CHARGER?

    i just need to charge 2 nicad batteries ( 1.2v C size ) which will be pemanently installed in this screwdriver ( the original batteries have long been discarded ) is the supplied circuit suitable for charging 2/ B type nicad batteries in series . . my main queerie is . . . is this circuit...
  2. polyal

    2.4v NICAD CHARGER?

    b&d 9018 i just need a generic charger and wondered if this circuit is valid the original charger is a wall wart 5v ac supply with an inline diode . . how good is that ♪♪:)
  3. polyal

    2.4v NICAD CHARGER?

    Q for the geeks I need to build a charger for a 2 cell electric screwdriver (2.4v) i found this circuit on utube will it work . . .thanks edit : op amp powered via pin 8/4( not shown )
  4. polyal

    treble control centre frequency

    thanks for the info ♪reg♪
  5. polyal

    treble control centre frequency

  6. polyal

    treble control centre frequency

    thanks for the info on the freq is there anyway now i can get a steeper slope to the shelving freq ♪reg♪
  7. polyal

    treble control centre frequency

    thanks ♪reg♪
  8. polyal

    treble control centre frequency

    how can i change the centre frequency from 12k (stated in the spec ) to 6k thanks ♪reg♪
  9. polyal

    CONVERT from 15-0-15v to 9v

    thanks for the reply it turned out to be a build fault due to using recycled strip board with cut track ( R10 was not connected to virtual earth ) it has now been rectified and giving a healthy 4v p/p sine wave thanks for your help . . well chuffed ♪reg♪
  10. polyal

    CONVERT from 15-0-15v to 9v

    it works spot on:)with either ground or -ve i'm getting a 1v p/p sine wave ♪♪ ( at the op amp o/p ) is there anyway i can squeeze another 1volt gain out of it it will be used for signal tracing through audio gear typically at line level ( mixers etc ) the circuit is from a vintage soundcraft...
  11. polyal

    CONVERT from 15-0-15v to 9v

    thanks . . i will try that regards reg ps is the pot grounded at the battery negative or should it be at the virtual earth ? ie is the signal relative to the batt negative
  12. polyal

    CONVERT from 15-0-15v to 9v

    i have a mains powered 1khz test tone oscillator i need to make portable i need to convert it from 15-0-15 split rail to 9v ( battery ) this circuit generated 10v p/p what modifications do i need to do to get about a 2v p/p sine wave cheers reg
  13. polyal

    ptc thermistor

    so you dont know either? ...somebody must be able to answer my queery CAN I REPLACE A SWITCHING PTC THERMISTOR WITH A RESETTING FUSE TYPE.. AS A HEAT SENSOR IN AN ELECTRIC DRILL POWER PACK in response to the 2 replies Thermistor temperature sensing is one of the most sensitive properties or...
  14. polyal

    ptc thermistor

    if i could sort it out myself i wouldn't be on this forum asking for advice ?? lets hope i can get a sensible response to repost my queery : can i replace a 'switching' ptc thermistor with a resetting 'fuse' type any sensible info would be appreciated
  15. polyal

    ptc thermistor

    i am not suggesting anything i want to replace a faulty thermistor please read the post....and what i do is my business... so if you dont know dont reply regards ps thermistors are passive components and modern batteries dont have intelligence its the associated active and passive component...
  16. polyal

    ptc thermistor

    can i use a fuse type ptc thermistor as a power tool ( drill ) heat sensor..so the charging process ceases when the battery pack reaches the permitted max temperature allowed by the charger circuitry the charging stops when the thermistor exceeds appx 600R
  17. polyal

    Triac Testing

    thanks for that are you saying that these devices are OK? although the 0.4 volts drop ( 100ohms ) is both ways so its seems its not the effect of a diode junction how do snubberless triacs measure? reg
  18. polyal

    Triac Testing

    I thought the resistances between terminals of a triac should read o/c with a ohmeter...i have a batch of BTA 20A 600B ( 10 ) that all read appx 100R or 0.4v between T1 and GATE ? is there an explanation for this apart from ' bin them they're faulty ' regards reg
  19. polyal

    connecting 2 transformers

    thanks for the replies.....i suppose if the primaries were wired in series it would become a 10.5v - 0 - 10.5v since there would be 120v across each primary ( and a combined VA ) polyal
  20. polyal

    connecting 2 transformers

    i have two identical transformers 240v / 21v sec can they be configured to give me 21-0-21 regards polyal
Top