One electrode probe is (F) with 6V AC is placed at the bottom of tank. Next probes are placed step by step above the bottom probe. When water is rising the the base of each transistor gets electrical connection to 6V AC through water and the corresponding probe. Which in turn makes the transistors conduct to glow LED and indicate the level of water. The ends of probes are connected to corresponding points in the circuit as shown in circuit diagram. Insulated Aluminum wires with end insulation removed will do for the probe. Arrange the probes in order on a PVC pipe according to the depth and immerse it in the tank. AC voltage is use to prevent electrolysis at the probes. So this setup will last really long. I guarantee at least a 2 years of maintenance free operation.That’s what I got and is still going.
list Components of Water level Detection
- T1 - T5 BC 548 or 2N2222
- R1-R5 2.2K 1/4 W
- R6-R10 22K 1/4 W
- D1 - D5 LED’s