It is a kind of voltage stabilized power supply composed of LM317 chip, which has the simplest form of fixed three-terminal voltage stabilized circuit and has the feature of adjustable output voltage.
Input Voltage：AC 110VV
Output voltage：DC 1.25V~12V（continuously adjustable）�
Output Current：200 MAA
Can be used as a small power supply, signal generator, logic signal tester，Sensor alarm has buzzer function, such as soil moisture alarm, temperature alarm, etc..

Today, I soldered the voltage regulator circuit. It was by far the most complicated circuit I soldered. The timer component didn't had holes in the circuit so I had to add extra wires, and glue down the timer component. I'll still need to connect this to the power cables later.

I worked on soldering the power supply cables. The positive one worked out great, and for the negative wire it was too much heated/tightened it too much with the grip so the wire got separated. I cleaned the extra solder and will redo this last part again.

I finished soldering the power supply cables and screwing the box!