A circuit that lets you operate a solenoid with a lower voltage signal is known as a simple solenoid driver circuit.
In essence, solaroids are electromagnets that transform electrical energy into mechanical motion.
Generally speaking they need a greater voltage than microcontrollers or other digital circuits can readily handle.
The driver circuit functions as a switch that permits the high current required to run the solenoid to be turned on and off by a low voltage control signal.
Circuit Working:
Parts List:
| Component Type | Description | Quantity |
|---|---|---|
| Resistors | 1k, 1/4 watt | 1 |
| 10k, 1/4 watt | 1 | |
| Capacitors | Ceramic 1nF | 1 |
| Semiconductors | IC 7812 | 1 |
| MOSFET IRF540 | 1 | |
| Diode 1N4007 | 1 | |
| Other Components | ON/OFF switch | 1 |
| 12V Solenoid | 1 |
The circuit that uses a switch and a low voltage power source to control a solenoid is described in this article.
The whole circuit design is seen in the image above.
You may try building it on a little circuit board as it is not that difficult to assemble.
Typically, a solenoid is activated by attaching 12V to its terminals and it is deactivated by cutting the electricity.
The solenoids on and off functions are controlled by this circuit using a MOSFET, a unique type of switch that operates on a lower voltage signal.
A crucial component of this circuit is the MOSFET IRF540.
There are a few factors to take into account while selecting a MOSFET:
The voltage required to turn it on, also known as the threshold voltage, in this instance the circuit supplies 5v which is sufficient for the MOSFET to turn on which requires 4V.
Its current handling capabilities is ample the MOSFET is rated for 10 amps at 5V while the solenoid may draw up to 1.2 amps.
Selecting a MOSFET rated for more current than what is really required is usually a smart idea.
When switched on, the resistance between its terminals should be as low as possible to prevent the voltage to the solenoid from being reduced.
At just 0.077 ohms the selected MOSFET has a very low on resistance.
If you are constructing a circuit for a different solenoid, you may get the information from a datasheet.
The 12V input supply is converted to 5V using a IC1 7812 Linear Regulator IC and when the switch is pressed, this voltage is sent to the MOSFETs gate pin via a 1k R1 current limiting resistor.
A 10k R2 resistor pulls the gate pin to ground when the switch is not pushed.
As a result, when the switch is not pushed the MOSFET remains off.
Ultimately, an anti parallel diode is inserted to stop the solenoid coil from draining into the power circuit.
Formulas:
Let us go over the main formula and factors to take into account while creating a solenoid driver circuit:
The solenoid current Isol:
Determine how much current the solenoid needs from the power source.
Isol = Vout / Rload
where,
- Vout is the IC 7812s output voltage 12V.
- The solenoids resistance is the Rload.
Verify that the voltage and current ratings of every component are appropriate for the demands of your particular solenoid and application.
In particular, if the solenoid demands a substantial amount of current, test the circuit thoroughly and take the MOSFETs heat dissipation into account.
Adapt component configurations and values to meet specific performance requirements if required make sure the MOSFET is properly heat-sunk.
How to Build:
To build a Simple Solenoid Driver Circuit follow the below mentioned steps for assembling.
- Gather all the components as mentioned in the above circuit diagram
- Connect MOSFET Q1 gate pin to the junction of R1 and R2 resistors.
- Connect MOSFET Q1 drain pin to one end of 12V solenoid, and the other end of 12V solenoid to positive supply.
- Connect source pin of MOSFET Q1 to ground.
- Connect IC1 7812 Vin pin between capacitor C1 and positive supply.
- Connect IC1 7812 ground pin to negative supply (0V).
- Connect Vout pin of IC1 7812 to R1 resistor through ON/OFF switch.
- Connect 12V Solenoid wires between the drain pin of MOSFET Q1 and +12V positive supply; and diode D1 is connected parallels to the solenoid wires.
Safety Measures:
- Understanding the safety risks is crucial while handling solenoids.
- Due to the high current and voltage that soldenoids may produce, it is critical to utilize components and a circuit that are rated appropriately.
- Moreover, solenoids should not be used in combustible or explosive conditions since they can ignite when turned on and off.
Conclusion:
To conclude, with the help of voltage regulator to supply the proper control signal and a MOSFET to act as a switch, this simple solenoid driver circuit enables you to operate a high power solenoid with a low voltage switch.