A header tank water level controller circuit is an electrical system that automatically controls the water level in a header tank.
The circuit keeps an eye on the tanks water level.
Float switches and conductive probes are common sensors used to determine if water is present or absent at a certain location.
Circuit Working:
Parts List:
| Category | Description | Quantity | Wattage |
|---|---|---|---|
| Resistors | 10k | 1 | 1/4 watt |
| 1k | 1 | 1/4 watt | |
| 2.2k | 4 | 1/4 watt | |
| Semiconductors | Transistors BC547 | 4 | |
| LED | 5mm 20mA | 1 | |
| Diode | 1N4148 | 1 | |
| Other Components | 12V DPDT Relay | 1 | |
| Metal water tank | 1 | ||
| Copper wires as probes | 2 |
The circuit regulates a water pumps power using transistors and a relay in response to a header tanks water level.
A probe attached to the metal tank senses the water level, the probe is not immersed and the circuit is turned off when the water level is low.
Because there is no current flowing across its base, transistor T1 is off.
Additionally transistor T2 is off because T1s collector to base junction which is functioning as a diode is obstructing its base current.
Because resistor R6 connects transistor T4s base to the positive side of the power supply, transistor T4 is operational.
The power supplies positive side generates current which then passes via resistor R6, transistor T4 and ground, by activating the relay the water pump is turned on.
The probe gradually submerges as the tanks water level rises.
The circuit between the probe and transistor T1s base is now complete.
The power supplies positive side generates current, which then passes via resistor R1, transistor T1 the probe and ground, transistor T1 is triggered by this.
Transistor T2 is turned off when current flowing from its base is diverted by T1, which is on.
Transistor T4 shuts off when T2 is turned off because its base is no longer linked to the power supplies positive side.
The water pump is turned off when the relay de energizes.
Formulas:
We can construct a basic circuit that uses transistors for switching and a relay to regulate the water pump or valve to create a water level controller circuit for a header tank.
Here are the formulas that incorporates in this circuit:
Voltage Divider Calculation:
The voltage levels in the tank at various water heights are calculated using the voltage divider circuit, which is made up of resistors and water probes.
Vout = Vin × R2 / R1+R2
where,
- Vin is the input voltage for 12V.
- R1 is the resistance of the resistor that is connected to probe from the 12V supply as 10k resistor.
- Total resistance of resistors from probe to ground is represented by R2
LED Current Limiting Resistor Calculation:
When the relay is triggered, the LED serves as an indication.
Determine the current limiting resistor RLED using:
RLED = Vsupply − VLED / ILED
where,
- The supply voltage 12V is denoted by Vsupply,
- The forward voltage drop of the LED (usually around 2V for a normal LED) is represented by VLED
- The required LED current (10–20mA) is indicated by ILED.
You may efficiently set up and modify your water level controller circuit with the aid of these formula and computations.
Depending on the intended use and particular component characteristics, adjustments could be required.
How to Build:
To build a Header Tank Water Level Controller Circuit follow the below mentioned steps for connections:
- Assemble all the necessary components mentioned in the circuit diagram above.
- Connect collector of transistor T1 to positive supply through resistor R2, connect base of transistor T1 to the left hand side of copper wire in the metal tank, connect the emitter of transistor T1 to ground.
- Connect collector of transistor T2 to positive supply of 12V through resistor R3, connect base of transistor T2 to right hand side of copper wire in the metal tank, connect emitter of transistor T2 to ground.
- Connect collector of transistor T3 to positive supply through relay coil pin and through D1 diode, connect base of transistor T3 through resistor R5, and emitter of transistor T3 to collector of transistor T4.
- Connect collector of transistor T4 to emitter of transistor T3, connect base of transistor T4 to resistor R6, connect emitter of transistor T4 to ground.
- Connect a LED and a resistor R4 in series from collector of transistor T3 to positive supply of 12V.
- Connect one end of resistor R1 to the positive supply to 12V and other end to the body of metal tank.
- Connect NO pin of one set of contact of the 12V relay to the collector of T3 transistor, and the pole of this set to the junction of T3 emitter and T4 collector.
Safety Notes:
- The circuit uses mains power, which has the potential to be dangerous.
- To reduce the risk of electrical shock proper building methods and components with the right voltage ratings are essential.
- Water damage might result from a pump failure or overflow caused by a defective circuit.
Conclusion:
Water pressure is automatically maintained by a header tank water level controller circuit, which regulates the pump according to the tanks fullness.
Although DIY circuits are possible, pre built choices or speaking with a licensed electrician are advised due to electrical safety concerns and the possibility of water damage.
References:
CONSTRUCTION OF AUTOMATIC WATER LEVEL CONTROLLER FOR BOTH OVERHEAD AND UNDERGROUND TANKS