working principle

There is also a complex version with better gradient effect, but more components, and the detailed principles are written.

Here we only talk about the simple ones. The picture below is from the official technical documentation of ti.

Taking the above figure as an example, if switch S is closed, pin 3 of chip A outputs high level.

At this time, the capacitor of pin 3 is discharged, and the potential on both sides is the same.

When the CA voltage reaches the voltage of pin 5, the output of pin 3 flips and is coupled to the next chip through the capacitor of pin 3.

By going back and forth in this way, the sequential output function is achieved, and the delay time of each channel is related to the peripheral resistance and capacitance of pins 6 and 7.

Formula: Th=1.1RC

# Component selection

Some people may think that these circuits are a bit extravagant compared to Taobao kits.

But in fact, if the quantity is large, placing orders yourself will not be much more valuable than Taobao.

As a soldering learning board, it is recommended to choose the cheapest electronic components. Can support domestic chips.

Because the component fails, the process of troubleshooting further tests whether you have a thorough grasp of the principles.

# related suggestion

The potentiometers and chips between these circuits are universal. If a certain circuit is damaged, the east wall can be removed to repair the west wall.

Sorted from simple to difficult, teachers are welcome to use them in teaching, but we hope that the URL of this open source page will be added to the courseware to show respect, thank you.

Analog circuit

1. NE555 Ambilight RGB driver
2. LM358 infrared sensor faucet circuit
3. NE555 dormitory magic lamp driver circuit
4. LM358 running water breathing lamp
5. LM358 pickup delay circuit
6. LM358 refrigerator closing reminder circuit
7. LM358 steering gear tester circuit
8. NE555 steering gear tester circuit
9. Dual-way Wien bridge sine wave generating circuit
10. NE5532 infrared reflective switch plus bandpass filtering
11. NE5532 music spectrum light

power circuit

1. Transistor constant voltage and constant current linear power supply
2. MC34063 single inductor buck-boost power supply
3. MC34063 temperature controlled fan
4. MC34063 light control lighting
5. LM358 constant voltage and constant current power supply

Digital circuits

1. CD4017 music doorbell
2. 74LS00 builds JK flip-flop
3. CD4013 three-person answering machine
4. CD4017 running water lamp clock