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    CRT High Voltage Power Supplies

    I've taken a few days to reflect on what you are saying, I am still somewhat confused. I can grasp the need for Positive HV on a television CRT, but why the do the deflection electrodes in an electrostatic CRT need to be close to ground in order to work ( how are they...
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    CRT High Voltage Power Supplies

    With CRT supplies, why do some circuits ground the positive and others ground the negative. Does making the cathode several thousand volts negative make the circuit physically safer, or are there other reasons. It seems most oscilloscopes use negative HV referenced to ground...
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    Generator protection

    # Typically the fuse or breaker is for protecting the wire feeders to and from the alternator/generator. 8A seems awfully small. Most cases the alternator is for emergency use so it would be run to failure. Fuses and breakers are just to protect the feeders. If you are...
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    Generator protection

    In the US, typically service fees are 2 wire 220V (L! & L2) with a ground. This allows for 220V and 110V receptacles. L1 to L2 = 220V, L1 or L2 to ground =110V A (220V), L1,L2 & Return wire) alternator can be connected by back feeding a 220v double pole breaker. Square ‘D’...
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    Generator protection

    An inverted eceptacle plug i
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    Generator protection

    Absolutely NOT! Extremely dangerous, violation of Electrical Codes, and Criminal
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    Generator protection

    When working with to pole lines, a two pole circuit breaker is better than fuses. If a single fuse blows you would still have one line connected to the utility; with a two pole circuit breaker both lines will be disconnected. Always use a rated DPDT swtch to isolate feeds
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    20A CB not activating

    You say you are using a 120V generator: is this true or is it an alternator? A generator produces Direct Current. If using an alternator you could use a transformer to reduce the voltage. If you have a generator feeding a DC motor and it is running, your probably not...
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    British Electronics correspondence course

    I found this little scope and schematic, and had fun restoring to operation. Does anyone know of the associated correspondence course. The scope has various outputs ( time base out, power supply, deflection plate direct connection points, etc. I would like to see the...
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    Real life dilemma: Help powering an AC device with DC

    Hopefully your battery has enough capacity to supply enough current to energize the solenoids.. Good luck!
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    Real life dilemma: Help powering an AC device with DC

    I recently repaired a similar (Sears) Chime unit. It used a synchronous motor to rotate a switch (integral to the circuit board) to play different chime melodies depending on which door switch was activated.. It was strictly AC, the solenoids were the shaded pole type and...
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    Unregulated power supplies

    I hope I'm not considered a Hi jacker of this thread, but on the subject of unregulated supplies......... I've replaced a few gel-cell battery jump start packs and find a common problem. Most units come with a wall-wart power supply. I've checked many and most are...
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    Transmitter Pi Tuning and Loading network design

    Thanks Duke, The Wikipedia site has a lot of the info I desire. I happened across a Summer 1965 Elementary Electronics. There is an article on constructing a Z bridge for measuring antenna resistance. Also the text described how one could determine the resonant...
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    Transmitter Pi Tuning and Loading network design

    Hey Duke, Is it possible you could scan me the article from your Amateur Radio Handbook. 3rd Edition RSGB 1961? Eddie
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    Transmitter Pi Tuning and Loading network design

    Is there a software circuit simulator out there that I can build a Pi followed with a T network, plug in values and observe the results?
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    Transmitter Pi Tuning and Loading network design

    I’m trying to get an understanding of how Pi Output tuning circuits are designed. It appears most radio transmitters are designed for a 50-75 Ohm load. Why is this? I’m thinking when coupled to an antenna, the loading control would be resonating it’s capacitor reactance with the inductance...
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    Resistor value

    Possibly it's wattage rating.
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    How is transformer impedance selected here:

    The 6AV6 feeds a 6EH8 followed by a 3000 ohm to 4 ohm output transformer. It would seem the designers would of used the same transformers for input and output if possible, to save cost of spec'ing two different transformers. I guess the Output transformer wouldn't...
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    How is transformer impedance selected here:

    I agree with you. The circuit in from a 1966 RCA tube manual (pg 544-545). The Circuit description says: "...Transformer T1 matches the voice coil impedance of the 4-ohm pm speaker....to the 2500 ohm input impedance of the 6AV6 amplifier stage....." It just seems by adding a 500k...
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    How is transformer impedance selected here:

    My question is; How/why are the values determined? As I originally stated: the primary Z is 4 ohms, the secondary is 25K ohms, The 25K ohm secondary is in series with a 500K ohm resistance to ground, The tuns ratio calculates to be 79:1. (square root of 25k divided by 4)...
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