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Recent content by rumpfy

  1. R

    Do anyone know about this device? (B-PS4-1002-OLEKTRON)

    look it up on google. It is a 115 to 400 MHz directional coupler. Plenty on ebay for $50. Being BNC connectors is probably 50 ohm. hope this helps.
  2. R

    Manual for a casette player - but don't know wich one

    camerart is correct, in my view. As a refugee from Philips, I can say that the code number system is according to the Philips 12NC coding system.
  3. R

    Measuring electricity usage at home with solar installed

    Electricity meters are watt.hour meters and NOT amp.hour meters. They are also NOT volt.amp.hour meters. Accordingly, all measurements must be taken with respect to phase. Clip-on ammeters dont do the job required. This next bit is a rant and slightly irrelevant. In Australia, the whole...
  4. R

    Driving this valve-Oh lordy what have I done???

    It sounds to me like it is a bistable valve. These things use a magnetic latching method. Pulse it to turn it on then remove the power, then pulse it again with reverse polarity to turn it off. These are used to conserve battery power. hope this helps, rumpfy
  5. R

    Fuel level

    In my car, the fuel gauge is a meter which is a hot wire type of unit. The drive current is obtained from a voltage regulator in the dashboard display unit. The supply voltage is passed through the float variable resistance unit (or sender), in the fuel tank. The current from this unit passes...
  6. R

    Setting ROHM BH1414K IC Circuit to 75us Pre-emphasis Curve

    The 50 usec pre-emphasis was used for TV sound receivers. The bandwidth for TV sound was I think up to 10kHz. The pre-emphasis of 75 usec was used for audio FM transmission up to 15khz. If you are using the circuit for an intercom type of application, I would suggest you dont worry too much...
  7. R

    Solar panel voltage

    Fraser, I have a small 12Volt panel (10 watt), which I use for keeping my tractor battery topped up. I checked its characteristics by measuring the cell voltage with varying loads on the cell. At no load, the cell voltage was about 21 volts. As the load increased, the cell voltage reduced. For...
  8. R

    Do offline, <=16A Electric vehicle chargers need to be power factor corrected?

    Depends on how many you want to make. For a one off for yourself, probably not. For a fully approved production item, probably 'yes'. Power mains distortion is a big problem for system supply quality reasons. In the future too, PF corrected supplies will have a marketing edge. I think my Apple...
  9. R

    Engine running detection

    I'm with Tuned Wolf. Measuring water flow by either pressure or flow is the way to go. Depending on your exact system, the pump could be running but delivering no water. If this happens with a centrifugal pump, it will overheat. Alternatively, if the pump is helical rotor, the pump will not like...
  10. R

    Fire in a server roon. Smoke/soot damage

    SRAM, I dont know which country you are in. Generally, the cable industry has been developing halogen free, low smoke cables for a number of years. The development of such cable was brought about because of fires doing serious damage. The conventional insulation and sheath material for internal...
  11. R

    reliable ignition amplifiers - A question for the old gits.

    Hi, i have an old 1991 mitsubishi with a BOSCH ignition control module in it. I think the same unit was used in General Motors vehicles as well. I am in Australia and the cars I refer to were australian built cars. The control module was switched from an inductive pick up coil. but I think there...
  12. R

    three-phase power transmission, circuits, etc.

    Hi PG, been out of radio range for a while but I see you are still looking at power transmission. The use of star or delta depends on where you are in the network. generally, the use of star is confined to residential or end user applications. Similarly, delta is confined almost universally to...
  13. R

    electricity meter

    I googled a few DDS844 references, and they all showed the numbers 5(20). My GUESS is the 20 (30) is the current rating and maybe the 5 is the calibration value. In Australia, there has been a huge love affair with electronic metering, and the electromechanical type has largely been superseded...
  14. R

    How to parallel two 2N3055 transistors = 120vac, 150 watts?

    Gary, I used to fiddle with this sort of stuff and the design I started with was a self oscillating multivibrator like the one you are showing us. It used a separate winding to drive the transistor bases. The problem with this design is that the transistors switch only by having the transformer...
  15. R

    Automotive: Points and Ignition Booster/Amplifiers

    Sign, In one of the posts, there is reference to sparking at the points. This sparking will dissipate some of the primary energy and thus give a reduced spark energy. This wont happen to the same extent in the transistor design but still and all, some protection is applied to the transistor to...
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