2sa1837/2sc4793 strange betas

darkfenriz · 17th December 2005, 10:29 PM

Hi
I've just got these bjt's with 'T' and without '2S' on their packs.
Measured betas and they are approx. 160 for pnp's and 70 for npn's. (I've measured 4 of both).
These betas seem low especially compared to 'same' transistors from ST I guess (also without '2S') with betas of about 200 both npn and pnp. Are these counterfeit or what? What is your experience with them?
looking forward to replies
regards

Christer · 17th December 2005, 10:49 PM

According to the Toshiba datasheets both types should have hFE between 100 and 320, so the NPNs seem suspect, at least.

darkfenriz · 18th December 2005, 10:51 PM

Yes, thank you Christer
But wouldn't it be strange for such cheap medium power bjt to be counterfeit?
I'm a bit confused, I thought that only pricier bjt couterfeits could be profitable for someone.
regards

Elso Kwak · 14th March 2006, 07:30 PM

Low betas are fake. Mines from Digikey are genuine measure the same for NPN & PNP.

17th December 2005, 10:29 PM	#1
darkfenriz diyAudio Member Join Date: Jun 2004 Location: Warsaw	2sa1837/2sc4793 strange betas Hi I've just got these bjt's with 'T' and without '2S' on their packs. Measured betas and they are approx. 160 for pnp's and 70 for npn's. (I've measured 4 of both). These betas seem low especially compared to 'same' transistors from ST I guess (also without '2S') with betas of about 200 both npn and pnp. Are these counterfeit or what? What is your experience with them? looking forward to replies regards

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17th December 2005, 10:49 PM	#2
Christer diyAudio Member Join Date: Sep 2002 Location: Sweden	According to the Toshiba datasheets both types should have hFE between 100 and 320, so the NPNs seem suspect, at least.

18th December 2005, 10:51 PM	#3
darkfenriz diyAudio Member Join Date: Jun 2004 Location: Warsaw	Yes, thank you Christer But wouldn't it be strange for such cheap medium power bjt to be counterfeit? I'm a bit confused, I thought that only pricier bjt couterfeits could be profitable for someone. regards

14th March 2006, 07:30 PM	#4
Elso Kwak Banned Join Date: Dec 2001 Location: Zamboanga, City of Flowers, Mindanao	Low betas are fake. Mines from Digikey are genuine measure the same for NPN & PNP.

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