How Tesla Coils Work

Everyone knows Tesla, but do you know what a Tesla coil is? Tesla coils are also called Tesla coils because they are directly transliterated from the English name "Tesla". This is a distributed parameter high-frequency series resonant transformer that can obtain high-frequency voltages of millions of volts.

The principle of the traditional Tesla coil is to use a transformer to boost the ordinary voltage, and then charge the resonant capacitor of the primary LC circuit. When it is charged to the discharge threshold, the spark gap discharge conducts, and the primary LC circuit generates series resonance, providing sufficient power to the secondary coil. The high excitation power is equal to the frequency of the secondary LC circuit, causing the inductance and distributed capacitance of the secondary coil to resonate in series. At this time, the discharge terminal voltage is the highest, and lightning is seen. In layman's terms, it is an artificial lightning maker. There are Tesla coil enthusiasts all over the world. They have made various devices and created dazzling artificial lightning, which is very beautiful.

How Tesla coils work

The principle of Tesla coil is a device that uses a transformer to boost ordinary voltage, and then discharges from the discharge terminal through a two-pole coil. The Tesla coil consists of two loops coupled through the coil. First, the power supply charges the capacitor C1. When the voltage of the capacitor is high When the threshold of the spark gap is exceeded to a certain extent, the spark gap breaks down the air and sparks, and a path is formed in the primary coil of the transformer. The energy oscillates between the capacitor C1 and the primary coil L1, and is transferred to the secondary coil through coupling. Secondary The coil is also an inductor, and the connection between the top cover C2 and the ground can be equivalent to a capacitor, so LC oscillation will also occur. When the two-stage oscillation frequency resonates at the same frequency, the energy of the primary circuit will surge to the secondary and the discharge end. The voltage peak will continue to increase until discharge.

Tesla coil production

The first is the materials required.

[Enameled wire] The diameter is 0.2-0.3, about half a catty, depending on the size of the secondary coil. You can buy it in the electronics market for 20-30 yuan;

[PVC pipe] One 50-75mm, length 30-50cm, one 100mm diameter, 10-20cm long, total price 10 yuan. Aluminum exhaust pipe, used as the discharge top, one meter long, about 80mm diameter, price 15 yuan The above two materials can be purchased at hardware stores or building materials markets.

[Induction cooker capacitor] 1200V 0.3UF, 10-30 pieces required, about 1.5 yuan each

[High-voltage power supply] You can use NE555, TL494 and other chips to drive the TV high-voltage package to generate high voltage above 20,000V, but a better way is to use a ZVS driver, which has high power, less heat, and stable and reliable operation.

Then there's the production process.

1. Wind the secondary coil and use enameled wire to wind 1000-1500 times on the PVC pipe with a diameter of 50-75mm;

2. Make the discharge top, as shown below, make it from an aluminum exhaust pipe. In order to facilitate fixation, you can clamp the aluminum pipe with two stainless steel bowls up and down, and drill holes in the middle to fix it with screws. Aluminum basins, stainless steel hollow balls, stainless steel bowls, plates, cans and other metal objects with large surface areas can also be used as the discharge top. It should be noted that the discharge top must be connected to the enameled wire at the upper end of the secondary coil;

3. Connect the discharge top and the enameled wire on the secondary coil with wires;

4. Make the primary coil and wind the thick wire around the 10cm diameter PVC pipe. In order to facilitate debugging, you can also peel the single-core copper wire and fix it on the pipe as shown in the figure below. Pay attention to the quality inspection of each turn. There is a gap

5. Make a primary capacitor array. Every 10 capacitors are connected in series to form a group. Multiple groups are connected in parallel as needed. For safety reasons, each capacitor must be connected in parallel with a 1m resistor;

6. To make a lighter, fix two metal objects on the insulator with a distance of 3-5mm. In order to dissipate heat, you can use several groups in series.

【Adjust resonance】

The key to making a Tesla coil is to resonate, that is, the primary LC frequency must be equal to the secondary LC frequency. After calculation, you will find that L1C1≠L2C2. This is the number of turns of the primary coil that you need to adjust to obtain the required inductance value. The number of turns of the primary coil should not be too few. When adjusting the number of turns cannot meet the resonance conditions, you can make a rough adjustment by increasing or decreasing the capacitor group, and then adjust the primary coil. After determining the approximate number of turns, connect the circuit and turn on the power to observe the discharge effect. , then cut off the power, and fine-tune the number of primary turns (such as 5.7, 8.2 turns) until the arc is the longest.

【Precautions】

Tesla coils are high-voltage equipment, and it is strictly prohibited to touch any part of the circuit when power is on! After these steps, a simple Tesla coil is completed. Turn on the power, and the lightning made by yourself will appear in front of you. The above is the working principle of Tesla coil. I hope it can inspire everyone.