2322 66. 93034_93113 Vishay BCcomponents PTC Thermistors, Overload Protection For Instrumentation FEATURES AND BENEFITS • Fast response time for rapid protection • Automatic resetting once overload is removed • No contacts to burn out • No thermal runaway • Operates on DC or AC voltage • Small size and rugged construction; see Component Outline drawing. DESCRIPTION Test and measuring instruments, such as oscilloscopes and digital multimeters, can be easily damaged if excessive voltages are applied across their input terminals. Simple and effective overload protection can be provided by connecting a high-voltage PTC thermistor in series with the instrument; see Typical connection of the PTC thermistor for digital multimeter protection drawing. Under normal conditions, the resistance of the PTC thermistor is low, so the test voltage will be measured by the instrument. Under an overload condition, the PTC thermistor will switch to its high-resistance state, absorbing the overload current and protecting the instrument. When the overload is removed, the PTC thermistor will return to its low-resistance state, ready to resume its protective function. ELECTRICAL DATA AND ORDERING INFORMATION NON-TRIP CURRENT (RMS VALUE) at 25 °C (mA) TRIP CURRENT (RMS VALUE) at 25 °C (mA) NOMINAL RESISTANCE at 25 °C (Ω) MAXIMUM(1) VOLTAGE (V) INSULATION VOLTAGE (V) CATALOG NUMBER 10 20 1600 ±300 600 − 2322 660 93034 10 50 400 ±100 600 >1000 2322 661 93113 Note 1. These PTCs can handle maximum voltage without series resistance. MECHANICAL DATA in millimeters Component outline. PHYSICAL DIMENSIONS in millimeters H L 30 ±3 20 ±3 T D 15.5 ±1.5 3.1 ±0.5 H D T MAX. MAX. F d MASS SPQ (g) PQ CATALOG NUMBER 5 4.5 5.08 0.6 ≈0.47 500 10000 2322 660 93034 10 6.5 8.12 0.8 ≈1.82 500 10000 2322 661 93113 F L ∅d CCB832 For dimensions, see Physical dimensions table. www.vishay.com 170 For technical questions contact: [email protected] Document Number: 29072 Revision: 10-Oct-03 2322 66. 93034_93113 Vishay BCcomponents PTC Thermistors, Overload Protection For Instrumentation TYPICAL CONNECTION OF THE PTC THERMISTOR FOR DIGITAL MULTIMETER PROTECTION. TYPICAL CURRENT/VOLTAGE CHARACTERISTIC for 2322 660 93034. MLD319 10 2 I RMS (mA) PTC thermistor Ω input 10 V INSTRUMENT A 1 MSB392 1 TYPICAL RESISTANCE/TEMPERATURE CHARACTERISTIC for 2322 660 93034. CCB915 109 1.5 V (DC) max. 550 Vpulse R (Ω) 10 2 10 V RMS (V) 10 3 TYPICAL RESISTANCE/TEMPERATURE CHARACTERISTIC for 2322 661 93113. CCB916 109 1.5 V (DC) max. 375 Vpulse R (Ω) 108 108 107 107 106 106 105 105 104 104 103 103 102 102 0 50 100 150 200 250 0 50 T (°C) Document Number: 29072 Revision: 10-Oct-03 For technical questions contact: [email protected] 100 150 200 T (°C) www.vishay.com 171