This post explains for the semiconductor D1761.
The Full Part Number is 2SD1761.
The function of this semiconductor is NPN Transistor.
The manufacturers of this product is Rohm.
See the preview image and the PDF file for more information.
Preview images :
Triple Diffused Planar NPN Silicon Transistor
1. Low collector saturation voltage
2. Excellent current characteristics of DC current gain
3. Large collector dissipation
4. Complementary pair with 2SB1187