How do I use a redstone repeater in my world to make the launcher fire items continuously? Can you tell me about the principle?

It can be done with a high frequency pulse. Because the launcher is set to fire one at a time with power on, with a high-frequency pulse you can achieve a quick switch from powered-on - unpowered - powered-on.

Repeater pulses, as shown in the picture, should pay attention to the startup method: first use the red stone torch to charge the whole circuit, then randomly knock off a red stone, and then immediately put it back. Try a few more times and you'll be successful. This pulse does not control the switch.

Repeaters have a delay, two repeaters with the same number of gears have the same delay time, which means that I can use one repeater to energize the other for a split second, and then after the delay, the other repeater will energize the other at the same time as the first repeater goes off, and so on, constituting a pulse.

Expanded:

Redstone Repeaters are the most common type of repeater. p>The Redstone Repeater is one of the basic components of the redstone system of the sandbox game Minecraft, and can be utilized to achieve many functions. The Redstone Repeater is a diode, a repeater, a delayer, and a D-locker. Repeaters are relatively easy to obtain, but they are also complex and can be used in a variety of ways.

Repeaters, while relatively easy to obtain, are complex and can be used in a variety of ways. The various possible methods are described below. These features are able to be utilized in series to reduce the number of repeaters needed for a circuit. Redstone wires are automatically connected to repeaters.

The Redstone Repeater has the following features:

The cube is able to repeat the signals it receives like a bridge, so that there is no need to use two non-gates for every 15 cubes when conducting electricity with Redstone wires.

The cube only accepts signals from a specific direction, working much like a diode in an electronic circuit.

The squares could delay the signal by 1-4 ticks (optional) so that timing circuits would no longer need a large number of inverters. Existing conventional repeaters/delays consisting only of redstone torches still work fine.

The cube can also accept a direct input from another redstone repeater or redstone comparator on the side to latch the state of the repeater.

The following items can be used as inputs to a repeater when placed behind it:

Redstone wires (cannot be connected across levels)

Redstone torches

Strongly or weakly charged non-transparent cubes

Various types of switches (levers, pushbuttons, pressure plates, etc.)

Another repeater pointing in the same direction

This cube can also receive direct inputs from another Redstone repeater or Redstone Comparator on the side to latch on to the state of the repeater. p>

The following items can receive output from the repeater when placed in front of it:

Redstone wire. (Cannot be connected across levels)

Any square that can be energized. (Non-transparent cubes, but not TNT, Fluorite, etc.)

Any device that can be controlled by redstone. (Doors, mine cart rails, note boxes, etc.)

Another repeater that points in the same direction.

Reference:

Baidu's Encyclopedia- Redstone Repeater