T
treez
Guest
Hi,
The attached is a delay circuit….when the PRIBIAS1 rail gets its 14V voltage, then Q20 holds Q19 off for some 40ms.
However, the base current of Q20 can only be 50uA max.
The Ic in Q20 must get to some 450uA in order for it to turn Q19 off.
The BC846ALT1G datasheet does not describe what happens to hfe at these extremely low currents.
Do you think the circuit will be OK?
BC846ALT1G NPN datasheet
https://www.onsemi.com/pub/Collateral/BC846ALT1-D.PDF
The attached is a delay circuit….when the PRIBIAS1 rail gets its 14V voltage, then Q20 holds Q19 off for some 40ms.
However, the base current of Q20 can only be 50uA max.
The Ic in Q20 must get to some 450uA in order for it to turn Q19 off.
The BC846ALT1G datasheet does not describe what happens to hfe at these extremely low currents.
Do you think the circuit will be OK?
BC846ALT1G NPN datasheet
https://www.onsemi.com/pub/Collateral/BC846ALT1-D.PDF