PTC Resettable Fuses

Our Semifuse PTC fuses manufactured by Fuzetec, are re-settable current fuses based on conductive polymer PTC (PPTC) technology. These solid-state PTC fuses will happily carry their rated “hold” current values until that rating is exceeded. If a short-circuit or other over-current condition occurs, the PTC fuse will heat up rapidly and its resistance increases to limit the through current to a safe level.

The PTC fuse will then remain in this “off” state until the applied voltage is removed and the PTC can cool down. On cooling, the PTC effectively then “resets” itself to its pre-fault rated current level, ready to protect your battery or other electrical appliance.  Our PTC range is extensive and has various form factors to suit your application; low-profile strap designs for batteries, SMD for on-board protection and radial-lead formats for general electrical equipment.

Semifuse PTC fuses are available in a wide range of “hold” current values from as low as 0.01A (SMD) up to 14A in the SFR16F (16V) radial lead series. Voltage ratings range from 6V (SMD) up to 240V in the SFRV series.  PTC fuses are often used to protect both primary and rechargeable batteries, automotive electrical circuits, computers and their accessories and other electrical equipment.

All Semifuse PTC re-settable fuses are operational between -40°C to 85°C, but the ambient temperature will affect the performance of the fuse.  Ambients above 23deg.C will cause the fuse to trip more quickly whereas temperatures below 23deg.C will result in a delayed response.  These “thermal de-rating” curves are shown on the pdf datasheet for each series to assist with product development.

All our PTC fuses carry the latest UL, CSA and TÜV approvals.

For further technical information, see our Frequently Asked Questions section

Call us today on 01606 871680 or complete the Contact us form, to discuss your application’s thermal sensor requirements.  Using our extensive technical knowledge and innovative supplier base, we will work with you to provide the optimum solution for your product.

  • Products
  • FAQs
  • SEMIFUSE SFSR Resettable PTC Fuses

    Our Semifuse SFSR re-settable PPTC fuse, from leading manufacturer Fuzetec, provides reliable, non-cycling protection against short circuits in rechargeable batteries and electronic circuits.

    • Current ratings: 1.2A – 4.2A
    • Voltage ratings; 15V – 30VDC
    • Nickel straps ideal for spot-welding directly to battery cells
  • SEMIFUSE SFLR Resettable Battery Strap PTC Fuses

    Our Semifuse SFLR PPTC fuses, from leading manufacturer Fuzetec, are ideal for high-power battery applications, providing reliable non-cycling protection against short-circuits and over-charging.

    • Current ratings; 1.9A to 9.0A
    • Voltages ratings; 15V to 20V (DC)
    • Nickel straps for direct spot welding between battery cells
  • SEMIFUSE SFLT Strap Resettable PTC Fuses

    Semifuse SFLT series re-settable PTC fuses (from Fuzetec) offer an improved level  of battery cell short-circuit protection, particularly in lower-power battery applications.

    • Current ratings: 0.7A to 3.4A
    • Voltage rating:   24VDC
    • Low-profile with nickel straps for spot-welding
  • Semifuse SFVT Ultra Slim PTC Fuse
    SEMIFUSE SFVT Ultra Slim Battery Strap PTC Fuses

    The SFVT series are ultra-slim PTC fuses and have a 20% lower temperature trip compared to our SFSR series.  They offer protection against over-current and over-temperature fault conditions.

    • Current ratings: 1.1A to 2.4A
    • Voltage rating: 16VDC
    • Nickel strap terminations for simplified battery assembly

    The Semifuse SFR16F series of resettable PPTC fuses from Fuzetec provide short-circuit protection in automotive electronic circuits for short circuit currents up to 100A, and other low voltage DC designs.

    • Current ratings 2.5A to 14A
    • Voltages – 16VDC
    • Temperature between: -40°C to +60°C
    • Radial leads (fixings)

    Our Semifuse SFR30F series of re-settable PPTC fuses, manufactured by Fuzetec, are ideal for use to protect battery chargers, computer peripherals, rechargeable batteries etc.

    They provide re-settable short-circuit protection in low-voltage DC circuits for short circuit currents up to 40A.

    • Current ratings 0.9A to 9A
    • Voltages – 30VDC
    • Temperature between: -40°C to +60°C
    • Radial leads (fixings)

    Manufactured by Fuzetec these radial leaded PTC fuses, provide re-settable short-circuit protection in low voltage DC circuits up to 60V for short circuit currents up to 40A.

    • Current ratings 0.05A to 3.75A
    • Voltages – 60VDC
    • Temperature between: -40°C to +60°C
    • Radial leads (fixings)
  • Semifuse SFRV 240V Resettable Radial Leaded PTC Fuse

    Re-settable PPTC fuses from Fuzetec are suitable for use with  transformers, electric motors and other electrical circuits, offering superior performance over conventional current fuses.

    • Current ratings – 0.05A to 2.0A
    • Max operating voltages – 240V AC/DC
    • Temperature between: -40°C to +60°C
    • Radial leads (fixings)
  • Semifuse SMD PTC Resettable Fuses

    Semifuse SMD PTC fuses are a very comprehensive range with footprints from 0603 up to 2920.  They offer a surface mount solution for a multitude of electronic and electrical applications.

    • Current ratings: 0.01A to 3.0A
    • Max operating voltages: 60V AC/DC
    • Temperature between: -40°C to +60°C