This is a really great product for making a miniature Tesla coil. It is very easy to assemble and the supplied components are of high quality. I was able to assemble it quickly and when testing it I was surprised at the output voltage. There is some variability between different kist I purchased but after a little adjusting all of them worked wonderfully. I am a retired high school teacher and an electronics engineer so these Tesla coils are important toys for me to use to demonstrate principles of physics when I now substitute teach in high school classes. If you buy one or more of there I believe you will be very satisfied with the performance of the product!
Verified purchase: Yes | Condition: Pre-owned
The circuit is OK and the board quality is good. At 3.7 volts the circuit uses a maximum of 2 amps or about 7.4 watts. The transistor heat sink is too small for this power consumption and the transistor heats up to 300F quite fast. The supplied transistor is too low of a wattage for this circuit. I changed mine to a 2N3055 transistor and replaced the resistor with a 3.3K . This allows the circuit to operate on up to 14.3 volts. At this voltage the circuit draws .540ma at about 7.7 watts. Even with the better transistor the heat sink is still way too small. The maximum length spark for this circuit is 1cm or about 3/8 of an inch. The shorter the spark the more current the circuit draws. The biggest problem with this circuit is the connection of the transformer wires to the circuit board in the correct orientation. I have posted a close up of the circuit board with the correct hook up. Letters on the board mark large and small diameter wires. For anyone that can't get their circuit to work this is probably what is wrong. It is also very important to completely scrape all of the enamel off the transformer wires where they go through the board so a good connection to the board can be made. Never exceed 4.8 volt input with the resistor that came with the board, if you did your transistor is toast. Also absolutely do not connect your high voltage output to the pin terminal block that came with the kit. The high voltage will track along the plastic, burning it to carbon, and short your output which = no spark.Read full review
Verified purchase: Yes | Condition: New
these inverter kits are fun to put together, even for a beginner at soldering, and they're very useful little electric lighters. they can be a fun toy too :) if you happen to get zapped by the output, it's comparable to an electric mosquito swatter. definitely no reason to get worried although i wouldn't touch it! xD a couple notes: you definitely want to solder a section of header pins, i chose 4 with the middle 2 removed and the tips bent inwards, across the output as mentioned in the instructions. otherwise you will get a loud squeal and possible damage (if you don't shut it off quickly) on startup, due to the lack of a load on the transformer. you can extend the output wires (make sure to use wire with appropriate insulation, such as ccfl backlight wire) but there must always be some form of load on the output. make sure to face the metal side of the transistor towards the heatsink. i'm not sure why but one picture in the listing shows it installed backwards. if you have some thermal paste put a little bit on the transistor before screwing it to the heatsink. and be aware that this transistor is very sensitive to adverse conditions, you may want to replace it with a higher quality model if you intend to push the limits of the transformer. when soldering the transformer to the board, i found the description of how the wires ought to be oriented rather confusing. the intended meaning is that the large winding ought to have one end soldered to the pad nearest the thick line, and the other shared with one end of the small (feedback) winding on the middle pad. then the other end of the small winding goes on the pad nearest the thin line. the ends joined together on the middle pad ought to be from opposite sides of the windings, for example the left side of the large winding joined to the right side of the small winding, or vice versa. don't forget that you have to remove the enamel from the transformer wires at the ends to be able to solder to them! if you wish to run the transformer on a higher voltage, even 5v, take note of the feedback resistor requirement. you WILL damage the transistor if you try to run the transformer on 5v with the included feedback resistor. either run it off an 18650 or increase that resistor's value :)Read full review
Verified purchase: Yes | Condition: New
Nice kit. Has all you need to make a high AC voltage, just add a 5V power supply and some high-voltage diodes to make a full-wave DC bridge to make a negative ion generator.
Verified purchase: Yes | Condition: New
The item works well, producing a smell of ozone within seconds, drawing approx 1 amp at 3.7 volts DC. Assembly was easy, The diode and resistor may be swapped in position compared to the photo, however this will not make an electrical difference provided to observe the diode polarity. The most difficult part of assembly and likely the cause of some people describing this as non-functional is the connection of the transformer. Observing the polarity or phase of the two independent secondary winding are very important. The two winding can be identified by the thicker and thin gauge wire. The placement of the gauge is marked by thick/thin lines near the holes. However if your connect power and it's not performing producing discharge, but drawing a modest amount of power then you may want to reverse one of the coils (not both!) so they are in phase. If you connect power and draw a considerable amount of current without output then disconnect and you likely have the two coils reversed. I suggest working out the center tap directly to the V+ prior to soldering. See Photo for the working wiring configuration. Note the "unusual" wiring arrangement not in the order of holes.Read full review
Verified purchase: Yes | Condition: New
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