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Station X · 15th Sep 2017, 10:07 am

I too was surprised that 101's collector wasn't at 18V. I put the difference down to volt drop in L102 which supplies all three transistors and the IC. If that's not the case then I guess the table is wrong.

Your calculations for T101's base do not take into account any current flowing into the base. This will cause a volt drop in the 22k resistor.

If the table is substantially correct, then the voltage on T101's base is very low and merits further investigation.

15th Sep 2017, 10:07 am	#69
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: Sailor T128 Marine Transmitter. I too was surprised that 101's collector wasn't at 18V. I put the difference down to volt drop in L102 which supplies all three transistors and the IC. If that's not the case then I guess the table is wrong. Your calculations for T101's base do not take into account any current flowing into the base. This will cause a volt drop in the 22k resistor. If the table is substantially correct, then the voltage on T101's base is very low and merits further investigation. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.