description: RCC (Ringing Choke Convertor) type switching power supply has less required components, low cost, no external clock control, and operates in a critical continuous state, which can easily realize current-type control. It is a single-pole system in structure and is easy to get fast and stable. Response, with automatic power limitation and other advantages. The RCC circuit is simple in principle, and the oscillation is generated by the resonance of the switching transformer and the main switching tube, and the auxiliary switching tube can adjust the duty ratio to adjust the output voltage. However, the duty cycle and operating frequency of the RCC power supply change with the use environment and internal parameters, making the current drive waveform of the control pole of the switch tube difficult to determine, which makes it difficult to select the device parameters, especially the transformer design. The traditional design mainly includes the nomogram method and the core area product AP calculation check method. These two methods are more practical in the calculation of the fixed frequency, but if the frequency is unknown, the above two methods cannot be used. The traditional method is to preset a frequency to the RCC power supply and then design the transformer. However, because the transformer parameters directly affect the working frequency of the power supply, the designed operating frequency of the transformer often differs greatly from the preset frequency and cannot work normally; the power supply parameters need to be repeatedly designed repeatedly, resulting in a large amount of initial design calculation, and In the later debugging, the actual frequency is difficult to match the theoretical value, resulting in the power supply not working in the best state of design. The full text of the RCC switching power supply circuit design based on the frequency calculation method can be found in the PDF document! Pipe fittings are the general name of the parts and components that play the role of connection, control, change direction, shunt, seal and support in the pipeline system. A pipe fitting is a part that joins pipes into a pipe. Pipe Precision Parts,Custom Pipe Parts,Fingerprint Door Lock,Automobile Exhaust Pipe Tianhui Machine Co.,Ltd , https://www.thcastings.com
This paper derives the frequency calculation formula and finds that the frequency is proportional to the input voltage and inversely proportional to the load current, the primary and secondary inductance. Under the determined input voltage and the known maximum output power, the initial and secondary turns of the transformer can be directly determined according to the input voltage, output voltage, rated operating frequency and duty ratio given by the power supply. All parameters solve the problem of repeated design and verification in high frequency transformer design. Based on this method, a 5V/10A switching power supply was designed, and the operating frequency and duty cycle of the power supply were verified. 
It mainly includes the following:
1. Pipe fittings used for connecting pipes with each other are: flange, splice, pipe hoop, clamp, sleeve, throat hoop, etc.
2. Pipe fittings that change the direction of the pipe: elbow and bend.
3. Pipe fittings for changing pipe diameter: reducing pipe (reducing pipe), reducing elbow, branch pipe table and reinforcing pipe.
4, add pipe branch fittings: three, four.
5. Pipe fittings for pipeline sealing: gasket, raw material belt, thread hemp, flange blind plate, pipe plug, blind plate, head, welding plug.
6. Pipe fittings for pipe fixing: clasp, hook, lifting ring, bracket, bracket, pipe card, etc.