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  1. duke37

    Questions conservation electronic

    You should read the posts. The silica gel saturates because it works, it needs drying to use it again. If the bag is sealed, then no moisture can get in and the gel will last forever. You seem to be obsessed with a cardboard box. This is permeable and will not help. Heating air will lower the...
  2. duke37

    Transformer - Number of turns?

    Ludens will tell you the wire thickness necessary for your output current. If the wire is too thin, then there will be too much heat produced and the transformer may fail due to insulation breakdown. You could get away with a thicker wire (5 times thicker than what?) but may not be able to get...
  3. duke37

    Basic Electronics

    Ohms law V = I * R If you were to connect B to ground, then the current would be 6/572 A The voltage at point A relative to ground would therefore be 60/572 V In other words a simple voltage divider.
  4. duke37

    Transformer - Number of turns?

    Transformers can be rewound. It can be difficult to take the laminations out without damage and re-.insert them. If the secondary is on the outside, then the primary can be left intact, Count the number of turns to get the turns/volt and multiply this by thirty. The space for primary and...
  5. duke37

    Questions regarding a rail gun build.

    I think you are treading dodgy ground here. I know nothing about rail guns but I think they are high power and a disposable camera would only tickle the storage capacitor. You will have to match the voltage and provide sufficient capacity.
  6. duke37

    Transformer - Number of turns?

    Well worth a read is some information by Ludens, see Ludens transformer. The core of the transformer is critical. Mains transformers use silicon iron laminations, High frequency switch mode supplies use a ferrite core, higher frequencies use iron dust cores. Radio frequencies often use...
  7. duke37

    Switch needs to remain on for certain time

    Please show a picture of the space you have. I would think that a circuit could be quite small. A 555 may not be able to control the motor so you will need a relay or mosfet. What is the load this circuit has to supply? For a 555, the biggest component will be a timing capacitor.
  8. duke37

    Weapon worries...

    I forget many things these days. I did remember to have my tea.:) I wonder whether the 4011 would run in this circuit. If it does, then it will go like a bat out of hell because of the very low hysteresis. If it does not oscillate, what would be the static state?
  9. duke37

    Weapon worries...

    KE0KOY wanted details of my little oscillator. The frequency is calculated to be 2.7/(RxC) It outputs 157kHz, 120Hz and modulation of the two. You may not want the low frequency RF on long wave. I often use harmonics on medium wave. I did not make a note of the component values, you can...
  10. duke37

    Questions conservation electronic

    We have been round these points before. 1. Low humidity is found where the air is heated. 5K heating drops the humidity a lot. Look up the tables. Low humidity is found in a refrigerator or freezer or close to a dehumidifier where the moisture is condensed on the evaporator. Do NOT put your...
  11. duke37

    Questions conservation electronic

    You can get plastic containers with rubber seals, I keep my biscuits in one. If you seal properly, the silica gel will last. Increase the temperature to reduce the air humidity This is how clothes and grain driers work. A refrigerator or dehumidifyer will take moisture out of the air. Put the...
  12. duke37

    How to subtract 10 ohms from a 200 ohm resistive load?

    You can put a resistor in parallel 1/A + 1/B = 1/C so 1/210 + 1/D = 1/200 or 1/D = 1/200 - 1/210 resistor D = 4200 Chose a resistor of the nearest preferred value say 3k9Ω or 4k7Ω
  13. duke37

    i'm in very much confusion :\ teach me masters!!!!

    It is easy to test the opersation of the relay but switching a motor needs the contacts to supply the current and to switch off when necessary. The motor will be loaded and will have inertia so the start current will be high. Turn off will generate a spark across the contacts due to the...
  14. duke37

    i'm in very much confusion :\ teach me masters!!!!

    I do not know any russian. The output power i calculate as 408W which matches the specification. 5000/60 *2*pi *0.78. The motor needs more input power since it is not 100% efficient. The starting torque and so current will be five times this. I think that there is no way you can simulate a...
  15. duke37

    Electronic Principles Home Work

    It would be better to use SI units. Why make things complcated with sub units? It would be better to use brackets to define your equation properly or rearrange to not need them. Wikipedia gives E0 as 8.85E-12 Farads/m Area 6cm2 = 6E-4m^2 Check this, the area could be 6cm by 6cm i.e. 36cm^2...
  16. duke37

    How can I identify switch transformers?

    Where did the transformers come from? What is the core made from? What is the resistance of the windings? What is the inductance of the windings? What do you want to use them for?
  17. duke37

    Pfaff sewing machine capacitor

    If this is a filter in the input supply, then the motor will work without it. Its purpose is to reduce radio interference which the sparks at the commutator produce. Check the motor before buying a new filter.
  18. duke37

    Weapon worries...

    You would not detect my oscillator a mile (1.6km) away, it is only powered by a PP3 battery and installed inside a 35mm plastic film can. Also, it will only upset those tuned to that particular frequency, your dirty pulses could affect many people. The cost of the oscillator should not exceed...
  19. duke37

    Circuit with transistor: PLEASE HELP

    I do not see any requirement for calculations, merely measurements. The battery? is connected with the negative at the bottom of the diagram and the positive at the top. Just how I like it, it does not matter which side it comes in. Vce is the voltage between collector and emitter, just...
  20. duke37

    Weapon worries...

    I have made a medium wave generator (CMOS 4093) driven by a little PP3 battery. I have used this to trace cables in a house and underground outside to a shed. Why do you need such high voltages? Pulses will have little energy at any one frequency but a much lower continuous power at one...
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