Transistor Replacement

[electronic novice]

Is there any replacement for BC550 transistor in the diagram below. Because it is not available in our place. thanks

 

[ronv]

I think almost anything would work.
2N2222
2N3904
BC547

are some common ones.

 

[electronic novice]

I placed BC547 as a replacement but its not working?

 

[Boncuk]

The BC550 has a fairly high HFE (640 to 800) depending on the suffix A, B or C.

Look for an equivalent with about the same HFE value.

Boncuk

 

[colin55]

Any transistor will work in that circuit for Q1. The gain is not critical AT ALL

It is technically a bad circuit as Q3 has no biasing.

The 100p between the microphone and base of the first transistor will not pass any waveform. It needs to be 100n.

The only other change is the removal of the diode. It changes the flickering effect and makes the circuit more realistic.

 

[More Coffee]

heres a few references for the BC 550


1. 2SC3069
2. 2SC3331U
3. 2SC3331V
4. 2SC6136
5. BC337-040
6. BC547C
7. BC550
8. ECG46
9. JC547C
10. JE9014D
11. JE9100G
12. LBC547C
13. LBC550
14. STL73D
15. STX112
16. STX616
17. TBC550

I have also built that circuit ,,it works well I had a single BC550 on hand ,

 

[electronic novice]

well i dont

 

[ronv]

Change C1 as suggested above.

 

[electronic novice]

if i changed C1 what will then be the new Q1? 547?

 

[ronv]

Yes, the 547 should work fine. Change the cap and if it doesn't work we can trouble shoot it.

 

[electronic novice]

ok, i'll rely on you ronv

 

[electronic novice]

ok thanks

 

[More Coffee]

well i dont

What I was getting at was ,,I think they are hard to find in general electronics,The only one I found that was retrievable was in a Darlington pair in an old RF modulator, out of a Samsung Cable converter box, one was epoxied to heck, I salvaged one.

I hope you get this circuit working ,
I used a flickering tea light led on a tube to look like a candle ,with a 7-segment display with my daughter's age lit up,and gave it too her for her birthday..really took the show amongst the kids..

I use this site to cross reference my transistors ,works in general and more often than not the data sheet is their to to a comparison..

https://alltransistors.com/crsearch...j=150°C&ft=300MHz&cc=6&hfe=110/220&mnf=&caps=

 

[electronic novice]

thanks more cofee i appreciated your help =).