2N3904 *MMBT3904 **PZT3904 PD Total Device Dissipation Derate above 25°C 625 5.0 350 2.8 1,000 8.0 mW mW/°C RθJC Thermal Resistance, Junction to Case 83.3 °C/W RθJA Thermal Resistance, Junction to Ambient 200 357 125 °C/W 2N3904 MMBT3904 PZT3904 EBC TO-92 SOT-23 SOT-223 Mark:1A C B E E B C C 2N3904 SC-43A plastic single-ended leaded (through hole) package; 3 leads SOT54 SYMBOL PARAMETER CONDITIONS MIN. MAX. UNIT VCBO collector-base voltage open emitter − 60 V VCEO collector-emitter voltage open base − 40 V VEBO emitter-base voltage open collector − 6V IC collector current (DC) − 200 mA ICM peak collector current − 300 mA 2N3904 *MMBT3904 **PZT3904 PD Total Device Dissipation Derate above 25°C 625 5.0 350 2.8 1,000 8.0 mW mW/°C RθJC Thermal Resistance, Junction to Case 83.3 °C/W RθJA Thermal Resistance, Junction to Ambient 200 357 125 °C/W 2N3904 MMBT3904 PZT3904 EBC TO-92 SOT-23 SOT-223 Mark:1A C B E E B C C

This is the Transistor Prototype PCB Design Kit with 2N3904 & 2N3906 Transistors.This kit is what you need to develop numerous different transistor circuits. It includes the extremely useful NightFire Prototype Transistor PCB along with some of the very popular 2N3904 NPN & 2N3906 PNP Transistors in the standard leaded TO-92 package. Compare pricing for NTE Electronics 2N3904 across 6 distributors and discover alternative parts, CAD models, technical specifications, datasheets, and more on Octopart. At 20mA, that's about 120 Ohms. The current gain depends on the collector current, but figure on 50. With a base current of 20mA, that's a collector current of way more than the 2N3904 can handle, so 20mA will saturate it thoroughly. You can probably get by with a lower base current. Look at a 2N3904 datasheet for gain at different collector ...