Tired of blown fuses? here is the solutions!
A DC electronic fuse circuit is like a superhero for your electronics.
It shields them from dangerous current surges.
Unlike clunky old fuses that need replacing, this circuit uses clever semiconductor components to constantly watch the current.
If things get too hot current wise, it springs into action and cuts the power before any damage is done.
Circuit Working:
Parts List:
| Component | Value/Type | Quantity |
|---|---|---|
| Resistors | ||
| R1 | Vbs x 1k | 1 |
| R2 | 0.22Ω | 1 |
| Semiconductors | ||
| SCR | C106, 4A / 250V | 1 |
| Transistor | 2N3055 | 1 |
| Other Components | ||
| Start/Reset button | 1 |
This DC electronic fuse boasts a lifetime without the need for replacement.
With a simple press of the start/reset button S1, it can be restored to functionality.
Upon pressing S1, C106 T1 activates, enabling current to flow to the consumer load via T1 and resistor R2.
Even upon releasing the start button current persists as long as it remains above a certain threshold.
However, when the current reroutes through transistor T2 2N3055 incorporated into the circuit alongside R2, the current through T1 drops below its holding level.
T2 and R2 are integrated into the electronic fuse to achieve this function.
If the voltage drop across R2 exceeds the base emitter diode trigger voltage of T2, the transistor conducts bypassing the thyristor.
The resistance value of R2 should be no less than 0.2 ohms ensuring that R2 multiplied by the fuse current equals 0.7V.
Once T2 bypasses T1, the current through the thyristor drops below its holding level, deactivating T1.
Consequently, the voltage drop across R2 falls below the base emitter trigger voltage of T2 causing the transistor to deactivate.
This results in the entire circuit shutting off.
Reactivation of the DC fuse is achieved by pressing the start/reset button.
The value of resistor R1 is determined by the supply voltage calculated by multiplying the supply voltage by 1k.
Connect the DC electronic fuse circuit to the PLUS line of the consumer load.
The voltage drop across the circuit remains under 1V.
Formula:
Below mentioned formula is used for DC electronic fuse:
R1 = V * 1 KΩ
- R1: This is the resistance value of the current-limiting resistor in a DC electronic fuse circuit, which is usually connected in series with the load, or the circuit component that has to be protected.
- Ohms Ω are used to measure it.
- V: This indicates the DC circuits supply voltage, which the electronic fuse is meant to guard.
- Volts V are used to measure it.
- 1 kΩ: The value of one kilo ohm (1,000 ohms) is constant.
The formulas purpose:
The right value of the current limiting resistor R1 in a DC electronic fuse circuit is determined using this formula.
The main function of the resistor is to safely restrict the amount of current that passes through the load in the event of an overload or short circuit.
Note:
The precise use would be determined by the particular circuit design and the function that R1 is given in that context.
How to Build:
To build Simple DC Electronic Fuse Circuit we need to follow the below mentioned steps:
Prepare the Circuit Board:
- Begin by preparing a suitable circuit board where you will assemble the components.
Mount Components:
- Mount the C106 T1, transistor T2, resistors R2, R1 and start/reset button S1 onto the circuit board.
- Refer to the schematic diagram for proper placement and orientation.
Connect Components:
- Solder the components onto the circuit board according to the circuit diagram.
- Ensure proper connections between each component.
Connect to Power Supply:
- Connect the positive terminal of the power supply to the PLUS line of the consumer load.
- Connect the negative terminal of the power supply to the common ground of the circuit.
Wire Start/Reset Button:
- Connect one terminal of the start/reset button S1 to the positive terminal of the power supply. Connect the other terminal of the button to the gate of the C106 T1.
Connect Resistors:
- Connect resistor R2 in series with the C106 T1 and the consumer load.
- The value of R2 should be at least 0.2 ohms.
- Calculate the value of resistor R1 based on the supply voltage V using the above formula.
- Connect R1 accordingly.
Wire Transistor T2:
- Wire transistor T2 in parallel with resistor R2 and C106 T1.
- Ensure the emitter, collector and base connections are properly connected according to the schematic.
Test and Adjust:
- Before finalizing the assembly test the circuit to ensure proper functionality.
- Adjust the circuit as necessary ensuring that the voltage drop across the circuit remains under 1V.
Finalize and Enclose:
- Once testing is successful, finalize the assembly by securing components and wires on the circuit board.
- Enclose the circuit in a suitable housing to protect it from external elements and ensure safety.
Testing and Operation:
- Test the electronic fuse by applying power and pressing the start/reset button S1.
- Verify that the circuit activates and deactivates as expected when the current exceeds or falls below the threshold.
Note:
- By following these steps and referring to the schematic diagram provided, you can build the described DC electronic fuse.
- Ensure safety precautions are taken when working with electrical components and soldering.
Conclusion:
The advantage of electronic fuse circuits lies in their ability to provide precise and adjustable protection as well as their ability to be reset and reused without needing replacement components.
They are commonly used in various applications where reliable overcurrent protection is required, such as in power supplies, motor drives and automotive electronics.
References:
Why and How to Effectively Use Electronic Fuses to Protect Sensitive Circuits