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Help needed, very confused.
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Posted on December 29, 2020 at 11:02:36 | ||
Posts: 85
Location: Louisiana Joined: November 1, 2019 |
Power supply is a 250-0-250 81 mA transformer with a 5AR4 rectifier. B+ voltage is 250V. At this point I must be doing something wrong. I thought that I had a very basic understanding of Ohm's law. Apparently not. I am still working on a 27-6SF5-45 guitar amplifier. I will try to attach a schematic of the power supply and circuit. I do not understand the measurements on the 45. 194 V on the plate, 1.5 V grid and 2.9 mV cathode. Using 200v (close to 194) on the chart, 45 mA crosses -30V nicely. To calculate a bias resistor isn't 30 divided by 0.045 A to get 670 ohms (I used a 750 ohm resistor as it is close). |