Here is the text of Chuck Adams VFO quiz. Answers to be posted when they are answered.
You want a quiz? What the heck, let's go for it......
1. Why is the diode capacitance a max with 0V at J2-2?
2. Why is the diode capacitance decreasing as voltage
at J2-2 (pin 2 of J2) increases?
3. Why is the diode reversed biased?
4. What is C103 doing?
5. Why is the voltage to J2 provided by the 78L08?
About +8 volts
6. When rig is powered up, 8V is applied to the pot.
Since we have R and we have I, then we have power
applied to the 50K or 100K pot. It must thermally
heat up and slightly change its resistance value.
Why does this not affect the rest of the circuit,
i.e. the voltage at J2-2 does not change over time?
*****DANGEROUS QUESTION****** Do not try this at home.
7. Why must one be careful when using the clip lead
and not connect it between pins 1 and 3 of J2?
****Again, do not do this. Please do not do this.
This is just a reminder to show you why you need to
look at schematics, think, carefully use the jumper,
think, and then think some more.****
8. On some rigs, you might see a small trimmer cap
in the Y5, RFC2, C28, and C29 part of the circuit. Why?