Distance between pin 1 and 2 is 14mm, between 3 and 4 is 17.5mm, distance between 2 and 3 is 10mm. Two specifications of printed board welded and leader, fully-enclosed, ultra-crystalline core, linearity better than 0.2%. Dielectric strength: higher than 6000V AC/1min. Fire resistance property: taking away flame, transformer keeps burning less than 10 seconds ( in accordance with UL94-VO). Operating temperature: -55--+85 Celsius Degree. relative humidity: not over 95%. Work frequency: 20Hz to 20KHz.