When to Use PTC Resettable Fuses and Metal Fuses?

Power Circuit Protection
,
1

Question: When should I put a PTC resettable fuse into my circuit over a one-shot metal fuse, and vice versa?
Answer: Scenarios with low voltage, small current, occasional malfunctions, but no issues with the product itself and thus no need for replacement are ideal places for PTC resettable fuses. Most other applications are better suited for metal one-shot fuses.

  • PTC Resettable Fuses are suitable for circuit environments with low voltage and small current. In such scenarios, the circuit may experience occasional malfunctions, but these malfunctions are not caused by damage to the product itself, and there is no need to frequently replace the fuse.

  • For example, in some small-scale electronic devices, the operating voltage and current are relatively low, such as the power circuits of some portable consumer electronics products (like MP3 players, small-sized electronic dictionaries, etc.). These devices may experience abnormal current due to external electromagnetic interference or short-term power fluctuations, but the devices themselves are not damaged. The resettable fuse can automatically recover in such cases, eliminating the need for users to replace the fuse, which is convenient for use.

  • On the other hand, metal Fuses are single-use. In other scenarios, especially those involving high voltage, large current, or situations where a malfunction may cause serious damage to the equipment, metal fuses are more appropriate. Because after a metal fuse blows, it can reliably cut off the circuit and prevent the spread of the malfunction. For example, in the circuits of high-power electrical appliances (such as electric water heaters, air conditioners, etc.), once an overcurrent situation occurs, the metal fuse will blow quickly to protect the safety of the appliance and the circuit.

More Littelfuse circuit protection products

Littelfuse Circuit Protection products provide stable and reliable signal transmission guarantee for all kinds of precision electronic devices by virtue of their precise adjustment relationship with capacitance, dynamic resistance, etc. in terms of high-frequency characteristics, and their performance is excellent in the industry.

More Q&A on Littelfuse Circuit Protection Products Technology:

I. Questions Related to Component Characteristics

  1. What are the classifications of gas discharge tubes?

  2. Littelfuse new MOV+Sidactor thyristor vehicle charging solution technological innovations

  3. In Littelfuse circuit protection products, what kind of current is I in I²t?

  4. What are the differences between discharge tubes and metal oxide varistors?

II. Questions Related to Selection

  1. How to select metal oxide varistors for overvoltage protection?

  2. Do Littelfuse overcurrent protection fuses/circuit breakers have self-resetting function?

  3. The difference in the selection of overvoltage / overcurrent between AC and DC input terminals?

  4. When to Use PTC Resettable Fuses and Metal Fuses?

  5. What parameters differ between surface mount and through hole fuse selections?

  6. Under what general circumstances can AC components be directly used in DC circuits?

  7. Can the method of paralleling small-capacity fuses be used to achieve the purpose of fast fusing?

III. Questions Related to Applications

  1. What design requirements for overcurrent and overvoltage protection?

  2. In which fields are gas discharge tubes mainly applied? Do they have directionality?

  3. Are overcurrent and overvoltage protection for AC/DC power inputs used in charging piles?

  4. Can Littelfuse Circuit Protection Products Protect Against Overvoltage and Overcurrent?

  5. How to understand the fuse explosion-proof test?

  6. How to specifically know the time of time-delay fusing fuses?