- Joined
- Nov 28, 2011
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Oh sh*t Trevor! How did you break your spine?
No, its 390Ω. I have a frequency meter coming, and I will fine tune the output by using a 10k pot. Thanks to everyone's input, I've calculated the RC network with my .47uf cap should have about 8.2kΩ. I'm actually sort of glad the provided circuit was a joke. It forced me to learn a lot about mosfets, etc! However, it's a dirty trick to play on an unsuspecting beginner like myself.The frequency is 1/(4.4*R*C) so 390k and 0.01μF is 58Hz and 390k with 0.47μF is 1.2Hz which is far too low. Is the resistor actually 390k?
Thanks Duke, but I replaced the .01μf with a .47μf.The 390R with 0.01μF will give 58kHz - far too high for a laminated transformer to handle . Posh valve audio amplifiers have trouble going to 10kHz. 1kHz would be nice.
If you are going to rectify the output then the frequency is not critical and I would not include an adjuster.
About 58cps. I'm using the power my house.So what frequency do you estimate you will get?
Thanks Duke. Where do you get the 4.4 in your formula?The frequency is 1/(4.4*R*C) so 390k and 0.01μF is 58Hz and 390k with 0.47μF is 1.2Hz which is far too low. Is the resistor actually 390k?
I have a book, remember them?
COS/MOS B-series Devices Databook 1st edition by SGS-THOMPSON MICROELECTRONICS.
They give details of the HCC4047B.
I am sure you could find details on the web in a short time.
I doubt if the frequency is very accurate which presumably is why a trimmer is included in the original circuit. The 58Hz is close to 60Hz which is used for the mains in your part of the world.
Do you need an accurate frequency if you are generating DC?