WATER LEVEL INDICATOR

Water level indicator can be used to measure the level of every conductive non-corrosive liquid for home and industries. The circuit is founded on five transistor switches. In order to drive the corresponding LED each transistor is switched on.

We supply the base with current passed through the water and through the electrode probes. (F) is one of the electrode probe 6V AC which is placed at the base of the tank. The other probes are then placed one by one above the base probe. The base of every transistor gets electrical connection when the water rises up to 6V AC through the water and corresponding probe.

When this process is done, the transistors conduct and glows the LED which indicates the level of water. Insulated Aluminum wires with edge insulation detached will work for the probe. The probes are arranged in array on a PVC pipe in accordance to the depth and plunge it to the tank.

To avoid electrolysis at the probes, AC voltage is used. This set up will therefore last really long. A 2-yr of maintenance free operation is guaranteed.

Points to note

For power supply, use a transformer with six voltage 500 mA output. Use of a rectifier is strictly prohibited.

For probes, the use of good value insulated Aluminum wires is recommended. If not available the Steel or Tin can be used. However use of Copper is strictly prohibited.

The type number of transistors to be used is not important. Any small signal (NPN) transistor will work comfortably. Examples of other suitable type numbers include: PN2222, BC337, BC546, BC107, ZTX300, BF494, and BEL187.

A plastic box that has holes to reveal the LEDs can be used to enclose the circuit.

The circuit is reliable, very simple and cost effective and many people have been able to assemble it without any problem.

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