The 220V AC will be available at the secondary of the transformer. The out puts of the TIP 122 transistors are amplified by four 2N 3055 transistors (two transistors for each half cycle) to drive the inverter transformer. The IC1 Cd4047 wired as an astable multivibrator produces two 180 degree out of phase 1/50 Hz pulse trains.These pulse trains are are preamplifes by the two TIP122 transistors. Somesort of cooling fan inside the project case may be a good choice. Normal electrolytic capacitors would overheat and explode. The 68uF Tantalum capacitors were chosen for their endurance. The powercord also needs to be secured to prevent accidents. You are dealing with 120VAC or 220VAC at respectible amperage so be careful. To be really safe you may want to include a primary and secundary fuse for your own protection. It is mandatory to include at least one suitable fuse and enclose this project in the correct casing. NTE’s replacement, NTE181, is an improved version of the 2N3771 and carries 90volts instead of the 40 volts and can dissipate 200W instead of 2N3771’s 150W. If this is the case, the 2N3771 power transistor is a good choice at 30Amps. If you intend to beef everything up with a couple kilowatts a standard (5″) cooling fan will also be required. It is imperative to mount Q1 and Q2 on large coolribs. If you are good with electronics all you have to do is replace the 2N3055’s and T1 accordingly for more output. Assume a transformer of about 15A and the chosen transistors of 2N3055 (15A) type, the inverter can supply about 300 watts with the parts shown. The power output is determined by transformer T1, and power transistors Q1 & Q2. If there is enough interest, I can modify this circuit to include a crow-bar circuit, battery backup, or more output in watts, or everything. This particular circuit can be constructed to handle up to 1 KiloWatt (1000 watt). Additional delivery time may result for some deliveries.If you live in Europe, Australia, or any other country with a 220VAC system, the only different is the transformer. * Freight delivery times stated are for average volume items with total order weight under 5kg. Your order can be delivered to anywhere throughout mainland New Zealand.

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