MMBT2222ALT1G by Onsemi is a NPN BJT transistor with 3 terminals, max power dissipation of 0.3W, and hFE of 75. Ideal for switching applications, it operates b/w -55 to 150 °C with a max collector-emitter voltage of 40V. This surface-mount device has a transition frequency of 300MHz and turn-on time of 35ns.
DS18B20U by Maxim Integrated is a 12-bit temperature sensor with 1-Wire interface. It operates b/w -55 to 125°C, offering ±0.5°C accuracy. Suitable for applications requiring digital output and surface mounting feature.