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  1. boombar

    460V DC to 400V DC How?

    Thanks Ante. This is interesting.
  2. boombar

    460V DC to 400V DC How?

    As I mentioned earlier, I'm using an old transformer I found. Just missing 400V. And it's not easy to order custom transformer here since they're not very cheap. I will probably benefit more by putting few transistors. That's why I chose this power supply. It didn't use transformer tap for 2...
  3. boombar

    460V DC to 400V DC How?

    Yeah. Decade is right. Screen grid need very low current. I overcalculated a bit and caused confusion. Sorry. Maximum screen grid power dissipation for 6L6GC is 5W. So screens for all four tubes will dissipate maximum of 20W (right?), that means 0.05A on 400V. Right? But I will not be driving...
  4. boombar

    460V DC to 400V DC How?

    And thank You Shahriar too.  :)))
  5. boombar

    460V DC to 400V DC How?

    Thank You Ante for Your reply. I found an old transformer i want to use for my tube amp. It's perfect, but mussing 400V for screen grid. I't doesn't realy need full 1A of current. Sorry. Just to supply four 6L6GC screen grid voltages, but don't want to blow something in power supply (instead of...
  6. boombar

    Timed Status Indication w/ Multicolor LEDs

    No need for microcontroller. Make detection when heater is on and off (comparator?) 1. When heater is on, signal from comparator powers red half of the LED, and keep green half off via inverter. 2. When heater turns off, red goes off, and green turns on. This signal drop trigers 555 which...
  7. boombar

    Simple remote gopher

    http://www.mitedu.freeserve.co.uk/Circuits/Interface/irext.htm
  8. boombar

    460V DC to 400V DC How?

    I need to lower voltage from 460V DC (sometimes goes even to 470V) to 400V DC. Need to supply up to 1A max. It's probably possible to achieve that with some zeners and a transistor... is it?
  9. boombar

    Radar Jammer?

    You CAN jam police radar by emitting radio waves in direction of radar (front). Laidar works the same way as radar, but instead of radio waves it uses light. The principle is the same, laidar uses laser beem which bounces of car and returns at differen wavelength. Doppler effect. Now, about IR...
  10. boombar

    digital amperemeter

    As I understood, they want to connect ampermeter to computer port and get data on monitor... If so, make ampermeter with 7107 chip. Download datasheet for it. In there You can find how to make ampermeter. 7106 drives 7-segment 3 1/2 LED display. So take 7-seg to BCD converter (like 74C915)...
  11. boombar

    Simple LED strobe

    Here's URL with tutorial and simple schematics. Look for picture for Astable operation (in the mddle of document). http://www.uoguelph.ca/~antoon/gadgets/555/555.html Some simple schematics and calculator for 555 can be found here: http://ourworld.compuserve.com/homepages/Bill_Bowden/555.htm...
  12. boombar

    Tracks Shape in RF PCBs are like two comb!

    It's a small CAPACITOR. I don't believe it's even a calculated one. It stands just to cancel verry small noise. Goes before active component so the noise doesn't get amplified to the level that effects signal quality. Think of it as twisted pair, only on PCB level. To be an inductor, it has to...
  13. boombar

    7106 resistance-meter auto-on howo

    Anybody know how to make ICL7106 based resistance-meter turn on automaticaly when resistance is connected and go off when resistace is removed. Something like stand-by. It's auto ranging meter with two ranges: 0-19 Ohm and 20-2000 Ohm. Measuring current must be lower than 1mA. Right now works...
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