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  1. majoco

    Panasonic Dect phone low emf option

    The OP has disappeared - another time waster.
  2. majoco

    Panasonic Dect phone low emf option

    Reading the instructions for my Panasonic KX-TG2722 phone (which after all is the phone we are talking about) it says "You can turn on/off one touch eco mode by pressing [R/ECO]. The default setting is "Normal" ". But it also says "you can reduce the base unit transmission power by up to 90% in...
  3. majoco

    Panasonic Dect phone low emf option

    Oops.... That was supposed to say "you wouldn't want to reduce the peak power" :eek:
  4. majoco

    WheatStone bridge

    The only person with a problem is Dabu and he hasn't been heard since Post #1. He's probably even more confused now than he ever was at the start.
  5. majoco

    WheatStone bridge

    Post #9 "I know that at balance point the current will be same in R1, R2 and in R3,R4 " This is NOTtrue. The current through R1 and R2 does not have to be the same as the current through R3 and R4 TO BALANCE THE BRIDGE. Perhaps you need to understand both of Kirchoff's Laws. How can current...
  6. majoco

    WheatStone bridge

    Waaay back you said "I know that at balance point the current will be same in R1, R2 and in R3,R4" - this in reference ti this diagram... Aaah - but it's not. As you (or somebody) said at the bottom.... the ratio of R1 to R2 is the same as the ratio of R3 to R4. The current through R1 and R2...
  7. majoco

    Solar panel measure circuit.

    But a 1N4733 is a 5.1volt zener diode - but if there's 12 volts across the two resistors then there's only 2.11 volts across the zener? That circuit will work to measure the voltage but I would have preferred a 10:1 divider or something like that - maybe the zener is there for protection? Where...
  8. majoco

    not so cordless drill

    I have had a small Ryobi cordless drill for many years that has two internal batteries about "C" or "AA" size. I often use it with the charger attached in a small bench vise for all sort of cleaning/polishing/wire brushing tasks. It has a planetary gearbox between the motor and the drill chuck...
  9. majoco

    Basic Pulse generation help

    Like I said before, all that bit of circuitry between pin 20 to pin 19 is just a bit of signal conditioning - it'll shape up the pulses and get rid of any interference - maybe the Mk1 version didn't have that and the signal went straight to those modules but they found that wasn't working well...
  10. majoco

    Basic Pulse generation help

    Here's something I don't understand. Nowhere in either test method you've sent to me does it say "observe the speedo" - all it says is "connect a 'scope to pin 20" and observe the waveform. Now in the schematic diagram pin 20 goes to a bit if circuitry and an output to pin 19 - NOWHERE does it...
  11. majoco

    Basic Pulse generation help

    I'm beginning to think that you need more than one 12v supply - especially as it says in the test diagram you sent " remove the assembly....with the connectors still connected". So you need to supply volts to all those pins - it may well be that not having something connected will inhibit...
  12. majoco

    Basic Pulse generation help

    The lowest speed is 1Hz which I suspect is too low to indicate but that's alright - we've shown that the pulses are pulling down pin 20. I suspect that the lowest indication on the speed will be 10mph or something like that so you want to adjust the frequency control so that you will have about...
  13. majoco

    Basic Pulse generation help

    Reconnect your LED across the input to the cluster like the diagram - it should flash showing that the pin 20 is being pulled up and down by the pulses. You'll need to slow the pulses right down so that you can see it.
  14. majoco

    12 volts deep cycle battery

    Wiki says: The Ampere-hour capacity of any battery is entirely dependent on the rate you discharge it. Most vehicle batteries are measured at the 10 Amp rate down to 1 volt per cell. We used to test aircraft NiCad batteries at the 40 Amp rate and metered every cell - if it didn't meet the...
  15. majoco

    Basic Pulse generation help

    Well, you've about done everything that I would have suggested! Have you put your 12volt LED from pin 20 to ground and see if that is flashing - you may have to turn the frequency down low on the lowest range. You don't need to go any higher in frequency than 85Hz as we calculated earlier (The...
  16. majoco

    Basic Pulse generation help

    You can't make a general statement like that! If the 2N2222 comes in a metal can it will have a little tab on the can near one of the pins - that will be the emitter, the base in the middle and then the collector which may or may not be connected to the metal can.
  17. majoco

    Basic Pulse generation help

    Ah - I didn't know that your LED had an in-built resistor! You had the LED from pin 20 to ground to indicate that there was voltage at pin 20 - so just disconnect the ground side and join it to the collector of the transistor. Any NPN low power transistor will do, I just said a 2N2222 as they...
  18. majoco

    How to design a transistor circuit that controls low-power devices

    You will - the more you play, the more you learn!
  19. majoco

    Basic Pulse generation help

    You need a simple interface from the pulse generator to the instrument cluster. Keep your resistor and LED connected to pin 20 but disconnect the other end from ground and connect it to the collector of a 2N2222 transistor. Connect the emitter of the transistor to ground and the base to a 1kohm...
  20. majoco

    Basic Pulse generation help

    What are you using to measure the voltage? A DMM with an input impedance of 10Mohms or more? The voltage that you read on pin 20 may be going through a high-ish value resistor to maybe the base of a transistor so you would expect a voltage there - how many volts are you getting? Section 3 says...
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