The 2N3904 is rated for a maximum of 40V between Collector and Emitter, and 200mA Collector current. Your circuit is only powered with 9V, and the current passing through each transistor is limited to less than 20mA, so any replacement that can handle eg. 20V and 100mA will be fine. Next is Electrical Characteristics.
BD139 - NPN SILICON TRANSISTORS, BD139-16, BD139-10, BD139, STMicroelectronics
DB107 Datasheet, DB107 PDF, DB107 Data sheet, DB107 manual, DB107 pdf, DB107, datenblatt, Electronics DB107, alldatasheet, free, datasheet, Datasheets, data sheet ...tran 2n3904 npn 60v 200ma gen purp to92 kn3904 datasheet (pdf) 1.1. kn3904s.pdf size:71k _kec semiconductor kn3904s technical data epitaxial planar npn transistor general purpose application. switching application. e features l b l dim millimeters low leakage current _ + 2.93 0.20 a b 1.30+0.20/-0.15 : icex=50na(max.) ; @vce=30v, veb=3v. wiki:Bluno Nano is An Arduino Nano with Bluetooth 4.0) which integrates a TI CC2540 BT 4.0 chip with the Arduino UNO development board. It allows wireless programming via BLE, supports Bluetooth HID, supports AT command to config the BLE, and you can upgrade BBC547 Transistor Features --- 1. Bi-Polar NPN Transistor 2. DC Current Gain (hFE) is 800 maximum 3. Continuous Collector current (IC) is 100mA 4. Emitter Bas...
tran 2n3904 npn 60v 200ma gen purp to92 ON Semiconductor offers a comprehensive portfolio of innovative energy efficient power and signal management, logic, discrete, and custom semiconductor solutions.2n3904 small signal npn transistor preliminary data silicon epitaxial planar npn transistor to-92 package suitable for through-hole pcb assembly the pnp complementary type is 2n3906 applications well suitable for tv and home appliance equipment small load switch transistor with Rev. A/AH 2007-11-13 MMBT2222A SMD General Purpose Transistor (NPN) www.taitroncomponents.com Page 2 of 3 Electrical Characteristics (T Ambient=25ºC unless noted otherwise)