555 Timer-Based Flyback Transformer Driver

My 24kV high voltage "Jacob's Ladder" from DIY flyback transformer driver using 555 timer. Creating an electric arcI've always wanted to create an electric arc but don't know how. Then I come across the theory that air breaks down at about 1MV/m (Mega Volts per meter) (24kV/in). That mean you need 1kV in order to get 1mm arc. So you need a higher voltage. One of the method is to use a flyback transformer that can be found from an old TV or an old CRT PC monitor. It could generate about 10 to 30 kV. Other method is to create a "tesla coil" which is quite complicated. Maybe it will become my next project. Flyback transformer and preparationFlybacks can be found in all types of monitors and screens that use a cathode ray tube (CRT),...

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Simplest Intercom

Using old phonesUsing your old phones, you could create personal "micro" telephone exchange as simple as above circuit.I manage to solder the test circuit less than a minute. Than connect the phone and test it.It works. So why 39 ohm?From Epanorama Dot Net,the correct value of the resistor should be a resistor that can limit the circuit current around 30mA total loop.The method is by replacing the resistor in the circuit with a variable resistor, plug in the phones, apply power and tune the currentwith the variable resistor so the current flow is 30mA.After that take out the variable resistor and measure the resistance/ohm across it.Find the fixed resistor with the nearest ohm reading to it and replace it to the circuit.Simplest CircuitTesting...

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Simple Cable Tester

Simple DIY Cable Continuity TesterHow to useThis simple cable tester can be used to check 2 wire cable such as coax cable, telephone cable, audio cable and etc.Power the circuit using 9V battery.Plug in the cable and push "TEST" button.The dummy resistor is connected to the end of the cable which has 75ohm resistor inside.The tester will show only 3 conditions, "SHORT", "OPEN" and "GOOD".How it worksThe method is to check resistance of the dummy resistor at the "Terminator".The idea is simple.Imagine there is a short circuit cable under testing.The wire will act as nearly zero ohm resistor thus making the voltage divider near the dummy resistor to divide the 9V into 4.5V.Calculate it your self [ ( 1k / ( 1k + 1k ) ) * 9V = 4.5V ].4.5V is below...

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Upgrading DivX Player Firmware

Upgrading DivX Player FirmwarePlanning to upgrade your DivX player using CD? Good idea but if anything happen, your player will be dead.In order to revive it, you need to re-flash it.Refer here for more information about re-flashing your DivX player.Upgrading a dead player - By DivXpert.You can download some recommended softwares from their site and try it out.Now the fun part, you need a hardware interface from your computer to the player.Recommended hardware interface by DivXpert is standard Serial Data Cable for mobile phone.So I built one.Identifying The Upgrade Port Open up your player and find the main PCB & the upgrade port. Most of them have 4 pins [3.3V],[TX],[RX],[GND]. Find the label for each pin under the PCB.What You...

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