Electronic – I need the full range from an LM34DZ, but I don’t have an 1N914 diode. Is there a replacement

I must confess I never tried this. But the series resistor has an important role: it is there to limit the current through the LED. If there's no resistor, the current may be limited in the end to a value which is too high for the LED or for the driver transistor. Theoretically you should graphically add the U-I characteristics of the diodes and the LED, and see on the the resulting characteristic what's the current for your Vcc value. But the main problem is that this current cannot be reliable predicted, since the U-I catalog characteristics of the diodes and LED give you an typical curve, and this curve will also shift with the temperature.

So while it may work, I wouldn't count on it working in every instance. But you may have some help from an unexpected place: the IC driving your LEDs. Sometimes the digital outputs have internal resistors or other ways to limit the output current, in order to avoid overloading them. So check the spec sheet for your attiny2313.

What Oli says, BUT BC337-40 (NPN) and BC327-40 (PNP) through hole TO92 transistors will meet 95% of your small transistor needs, and they have the direct equivalents of BC817 / BC807. The SMD versions are available in Asia as Leshan Radio parts (NPN & PNP through hole and SMD) with similar part numbers - LRC817, LRC807. These are genuine Motorola mask parts made by a joint venture company between Motorola and LR. They have a range of older lower tech Motorola parts plus their own parts as well. Some of their own parts are very useful.

LR transistors page 1/3

For larger wattages, higher voltage or current, low noise high FT etc search Digikey [As trav1s suggests] for "transistor" follow the yellow brick road (menu selections) to the relevant selector guide and enter required parameters. Digikey transistors end of yellow brick road is here . Then sort by price and choose the cheapest in stock at the required volume - or use this as a guide to buy elsewhere. Consider using only ROHS compliant parts.

If a part is too special to succumb to these methods, ask us here with a specific design question.

Taiwanese CETSEMI also make some extremely nice transistors and small MOSFETs. The CETSemi CES2310 will do most things that an amateur would expect a SOT23 N Channel MOSFET to do.