BC 548C = BC 550C ?? - Electronic Circuits Projects Diagrams Free

Charon102 · 8th January 2005, 05:37 PM

Hello

I like to build a simple circuit for testing crystals. You can find the schematic here: http://3dcoders.bugpower.ch/quarztest.gif

I didn`t find all parts in my small stock, so I hope you can give me some suggestions for alternative parts. I`ve a lot transistors but no BC 550C. I looked in the datasheet and find out that 548C has nearly the same parameters.
Would the schematic work if I build it with BC 548C?

I also don`t have 4.7n / 100p capacitors. Can I also replace them with other capacitors who have parapmeters in similar range?

Greetings KarimF. (Electonic newbie)

williB · 8th January 2005, 05:51 PM

http://www1.jaycar.com.au/images_uploaded/BC549550.PDF

the PDF..
for comparison purposes
a 2n2222

http://www1.jaycar.com.au/images_uploaded/BC549550.PDF

Exo · 8th January 2005, 06:17 PM

Yes, there are little diffirences in max. voltages but you only use 5V anyway, so I think it should work.

Russlk · 8th January 2005, 10:04 PM

Almost any NPN transistor will work as long as the Ft is higher than the crystal frequency. Also, note that overtone crystals will oscillate at the fundamental frequency in this circuit, not the design frequency. The cap values are not critical, but don't stray too far from those given.

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8th January 2005, 05:37 PM	(permalink)
Charon102	BC 548C = BC 550C ?? Hello I like to build a simple circuit for testing crystals. You can find the schematic here: http://3dcoders.bugpower.ch/quarztest.gif I didn`t find all parts in my small stock, so I hope you can give me some suggestions for alternative parts. I`ve a lot transistors but no BC 550C. I looked in the datasheet and find out that 548C has nearly the same parameters. Would the schematic work if I build it with BC 548C? I also don`t have 4.7n / 100p capacitors. Can I also replace them with other capacitors who have parapmeters in similar range? Greetings KarimF. (Electonic newbie)

8th January 2005, 05:51 PM	(permalink)
williB	http://www1.jaycar.com.au/images_uploaded/BC549550.PDF the PDF.. for comparison purposes a 2n2222 http://www1.jaycar.com.au/images_uploaded/BC549550.PDF

8th January 2005, 06:17 PM	(permalink)
Exo	Yes, there are little diffirences in max. voltages but you only use 5V anyway, so I think it should work.

8th January 2005, 10:04 PM	(permalink)
Russlk	Almost any NPN transistor will work as long as the Ft is higher than the crystal frequency. Also, note that overtone crystals will oscillate at the fundamental frequency in this circuit, not the design frequency. The cap values are not critical, but don't stray too far from those given. __________________ see my website: www.geocities.com/russlk