Transistor variants - interchangeable?

[tigger01]

Hi,

Can anyone tell me if the following 2 transistors are interchangeable?

2SC2240GR
2SC2240BL

or these 2?

2SA970GR
2SA970BL

I can only find generic datasheets for 2SC2240 and 2SA970.

If they have the same specs, what do the last 2 letters signify?

Thanks,

Neil

[anatech]

Hi Neil,
The suffix represents the beta (gain) range of the parts. If you look at the data sheets, somewhere you should see where they spec the gain ranges and you will see those letter codes.

-Chris

[AndrewT]

Hi,
and due to the overlap in the ranges, devices from either range can have the same gain.

[anatech]

Hi Andrew,
Very true, and expected. I suspect they test a few and label the entire batch. Therefore the gain range suffix is only probability (and also one reason I test everything before I use it).

-Chris

[AndrewT]

Originally posted by anatech
I suspect they test a few and label the entire batch.

I suspect computer selection is putting them into boxes that generate the highest return (selling price)
High Vce, or high gain, or low noise would be three parameters that we users will tend to pay extra for. I guess this is what is done with the BC540 & BC550 families.

[Gold_xyz]

For Toshiba small signal bjt that means (2SC1815)

O = hFE 70..140
Y = hFE 120..240
GR = hFE 200..400
BL = hFE 350..700

2SC2240
http://www.semicon.toshiba.co.jp/doc...eet_030325.pdf
2SA970
http://www.semicon.toshiba.co.jp/doc...eet_030324.pdf

[anatech]

Hi Gold_xyz,
What's nice is that they keep the gain range suffixes the same across transistor types too.

-Chris

[Gold_xyz]

Hi

Also I have wondered a many times if it is possible to change a bjt with a different gain. (same model)
all perhaps depends on the circuit in which it works.

A Idea is to select the bjt with a multimeter that can measure hFE
and choose that with the nearest hFE.

[anatech]

Hi Gold_xyz,
In most circuits, probably.

-Chris

[AndrewT]

Originally posted by Gold_xyz
A Idea is to select the bjt with a multimeter that can measure hFE
and choose that with the nearest hFE.

have a look at the datasheets. They specify what currents and temperatures they use when defining the gain.
Your multimeter won't tell you what current it has used to take the measurement.
DMM hFE measurement is almost certainly based on constant base current. The meter then outputs the collector current as a gain value. This is rather different from the hFE vs Ic values given in the datasheet.