BD400 transistor equivalent.

[vari21]

hello everyone.
im looking for the right equivalent of bd400 transistor

BD400, SILICON, NPN, TRANSISTOR.
Type Designator: BD400
Material of Transistor: Si
Polarity: NPN
Maximum Collector Power Dissipation (Pc): 15 W
Maximum Collector-Base Voltage |Vcb|: 170 V
Maximum Collector-Emitter Voltage |Vce|: 100 V
Maximum Emitter-Base Voltage |Veb|: 7 V
Maximum Collector Current |Ic max|: 1 A
Max. Operating Junction Temperature (Tj): 150 °C
Transition Frequency (ft): 0.5 MHz
Forward Current Transfer Ratio (hFE), MIN: 40
Package: TO126
i ve uploaded a picture of the transistor, and the shematics.the BD400 transistor in the shematics isT104 just to show were it is located.
i appreciate any help thanks.

 

[bertus]

Hello,

It is weird that a BD400 with an Ft of only 0.5 MHz is used in a 27 MHz transmitter.
For that posistion you would need a transistor with a Ft of at least 100 MHz, to have any effect.

Bertus

 

[vari21]

Hello bertus thanks for your post , i ve used this website to grab information about that transistor.
https://alltransistors.com/

 

[bertus]

Hello,

I would expect a HF transistor on that position, rather than a power transistor.
The 2N3866, 2N3553 or BFY50 come in mind.

Bertus

 

[vari21]

thanks for your recommandations bertus ,anyway when i opened the transmiter i found that transistor bd400 located t104 and it seems it s the original from factory.i think it s a power transistor because it is connected to the battery terminal through dr101 and c103.

 

[bertus]

Hello,

It is also strange that in the pulse part of the schematic, the transistor types are given, but not in the RF part.
Where did you find the schematic?
Was it on a website?
Perhaps there is more info over there.

Bertus

 

[vari21]

the shematics can be found online just type varioprop12s on google.i ve uploaded another shematics not in english but in german i think it s the original one.

 

[bertus]

Hello,

Again no transistor types given.
I found a similar schematic here:
http://wiki.rc-network.de/index.php/Datei:Varioprop_8SAM_1.JPG
Looking at the inner of the system, the power can not be that much:
http://wiki.rc-network.de/index.php/Datei:Varioprop12S_3.jpg

Bertus

 

[vari21]

hi bertus ,yes this radio is 1.3w it is powered with 12v battery i think

 

[bertus]

Hello,

The 2N3866 will be capable of about 1 Watt.
The 2N4427 (mentioned in the 2N3866 datasheet) will work better on 12 Volts and also be capable of about 1 Watt.
The 2N3553 will be capable of about 3 Watt.

Bertus

 

[vari21]

hello bertus,
which one of the given 3 transistors do you think will work on my radio i will order it right now.
buy the way i ve got in my box the 2N2219 what do you think about it?

 

[bertus]

Hello,

The 2N2219 has only a max power of 800 mW.
Using it as amplifier it will likely put out about 400 mW max.

Bertus

 

[aurelZ]

It is weird that a BD400 with an Ft of only 0.5 MHz is used in a 27 MHz transmitter.
For that posistion you would need a transistor with a Ft of at least 100 MHz, to have any effect.
agreed ..this must be some kind of FAKE...
If you can find old crt tv use transistors from chrome amplifiers even are lower freq some of them work up to 150Mhz
and on 12 V power you can build solid RF amp.

 

[vari21]

hi bertus ,so do you think the 2N3553 will do the job since it s 3w ,or the 2N3866 is much better
please could you confirm thanks.