I have a three pin phototransistor and have designed a circuit using a two pin(i.e without the base) how can I do the connection this being the only availlable phototransistor as of now?
Help me identify the pins( hint it has a tag).

 

Can you supply us with a part number for your phototransistor?

hgmjr

 

The tag is the flag on a TO-18 can that identifies the emitter lead. The next closest lead is the base, and is not usually used with a phototransistor. The remaining lead is the collector. Base current is pretty weenie, so use a large resistor in the collector current for a good signal swing - something like 47 - 100K.

 

further , should I connect the base or leave hanging?

 

Leave the base unconnected.

 

If you can provide a part number it would make it easier to provide more assistance.

hgmjr