DC boost circuit for shrimp traps

Circuit Principle The circuit is shown in Figure 1. The circuit is mainly composed of five parts: oscillation, boost, rectification, trigger and discharge output. R1, C1, R2, D1, D2, VT and L1, L2 form an oscillation circuit. Among them, L2 is the feedback coil. Its oscillation frequency is about tens of kilohertz. The pulse voltage generated by the oscillation is inductively boosted by L3, and the DC voltage obtained after rectification by D3~D8 is charged to the energy storage capacitor C3 through A and B (both ends of A and B are placed in the electrodes of seawater through wires); On the other hand, C2 is also charged through R3. When the voltage across C2 reaches the turn-on voltage of trigger diode D9. The thyristor SCR is triggered to conduct, and the energy storage capacitor C3 discharges to terminals A and B through the SCR, causing the shrimp between the electrodes in the sea to be stunned by electricity and be salvaged. in. R3, R4, w and C2 form a phase shift circuit. Adjust the variable resistor W to change the charging time of C2, thereby controlling the discharge frequency of C3 to achieve the ideal shrimp fishing effect. The component selection oscillator tube VT is a high-power tube, requiring BVceo>200V. 1cm>8A. Such as C3995. The radiator area should not be less than 75cm2. If there is no such tube. Four 3DDl5Ds can be used in parallel (as shown in Figure 2). But the parameters of these four tubes need to be as consistent as possible. This prevents individual tubes from burning out due to large performance differences and uneven heating. R2 uses a 10Ω/10W cement resistor: D9 is a trigger diode DB3 with a breakdown voltage of 30V. SCR uses a 20A bolt-type one-way thyristor with a voltage resistance of 600V. Such as EGE06-06. Its appearance and pins are shown in Figure 3. C3 uses a 25μ, 450V oil-immersed capacitor. It is worth mentioning that if this capacitor is an electrolytic capacitor. Ineffective. And easily damaged. The production and debugging of pulse transformer B needs to be made by yourself. The magnetic core adopts the linear output transformer magnetic core of a 21-inch color TV. First make a frame with insulating paper, and then use Φ1.2mm enameled wire to wind 24T around the frame to make L1. Use 0.7mm enameled wire to wind 12T to make L2. After winding L2, wrap it twice with insulating paper for insulation to prevent high-voltage ignition. Then use Φ0.4mm enameled wire to wrap 300T as the output coil L3. Wind the wire package. When loading the magnetic core. Add 1-2 pads made of insulating paper to the butt end of the magnetic core to leave a magnetic gap in the core to prevent magnetic saturation. The ferrite core is easily broken, so when installing the core, insert it vertically into the wire package slowly and forcefully, and do not knock hard to avoid damage to the core. If possible, the wound pulse transformer can be dipped in paint to make it moisture-proof. Improve insulation performance. Connected to ends A and B are metal rods and fishnets. A 2-meter-long bamboo pole can be used as a hand pole. Connect A and B to the metal rod and fishnet through multi-strand rubber wires, as shown in Figure 4. Fish net hoops are made of metal wire. Due to the harsh environment used, it is better not to use ordinary iron wire for metal rods and fishnet hoops. It is best to use copper wire or stainless steel wire with a diameter of 6mm or more to avoid rust and seriously affect the shrimp fishing effect. After the components are welded correctly. Do not connect to L3 first, and debug the low-voltage oscillation part. If you hear a "squeak" sound. It means that the circuit has started to oscillate, then connect to L3; if the circuit does not stop to oscillate. Just interchange the polarity of feedback coil L2. After the circuit starts to vibrate, connect to L3 and debug the high-voltage part: use a 220V, 100W light bulb as the load and connect to terminals A and B. At this time, if the light bulb goes off and on. And it is very bright when it shines. And it makes a "Woo-Woo-Woo" sound, indicating that the production is basically successful. Adjust w so that the frequency of the bulb flashing is three times every two seconds, and it can be used in the sea. Common troubleshooting 1. The circuit does not vibrate and no "squeaking" oscillating sound is heard after the power is turned on. Indicates that the circuit has stopped oscillating. If the oscillation part is damaged or there is a short circuit in the high-voltage part, the circuit will not vibrate. When checking, first disconnect L3, if you hear a "squeaking" sound. It shows that there is a short circuit in the high voltage part, and focus on checking whether the thyristor and energy storage capacitor have broken down. If you don't hear a "squeaking" sound, the oscillation part is faulty. Check whether the oscillation tube is damaged, etc. If the oscillation tube is composed of four 3DDl5D, after damaging one of them. Don't just replace this tube. The four tubes should be replaced together to avoid hidden dangers caused by inconsistent parameters of the old and new tubes. 2. If there is no high-voltage discharge, the circuit will vibrate. But when using a 220V, 1OOW light bulb as the load, the light bulb does not flash. Check whether the L3 connector is detached or broken by corrosion, and whether the thyristor is open circuit. Whether the energy storage capacitor C3 can be charged and discharged, etc. 3. The discharge frequency is not adjustable. The discharge frequency is too fast or too slow or cannot be adjusted. All related to R3, R4, W and C2. A change in one parameter of these components will cause a change in the discharge frequency. Not conducive to catching shrimp. At this time. Check whether the adjustable resistor W is in poor contact, whether the resistance values ​​of R3 and R4 have changed, whether C2 is damaged, etc. This shrimp catching machine is suitable for catching shrimp in seawater or brackish water farms. If used for shrimp fishing in freshwater rivers. Change the number of turns of L3 appropriately.