mstechca
New Member
I am able to fine tune the frequency by pushing a button, and using the 4040 binary counter.
In order for me to obtain good steps, I must place some capacitors in parallel, and some capacitors in series, because there is no store that sells capacitors in exact multiples.
I want capacitance to be from 1 to about 16 pF.
If I were to use single capacitors, then the bits in the counter (if I only use 4) will be as follows.
Bit 0: 1.2pF
Bit 1: 2.2pF
Bit 2: 4.7pF
Bit 3: 8.2pF
Here's the problem. When counting, I want to see:
1.2pF, 2.4pF, 3.6pF, 4.8pF, 6.0pF.... and so on.
According to the bits above, I would get:
1.2pF, 2.2pF, 3.4pF, 4.7pF, 5.9pF, 6.9pF, 8.1pF, 8.2pF.... and so on.
As you can see, the count is uneven.
Are there any better capacitor values that suit this application?
I want the even-most count without making my circuit consist of 99% capacitors.
In order for me to obtain good steps, I must place some capacitors in parallel, and some capacitors in series, because there is no store that sells capacitors in exact multiples.
I want capacitance to be from 1 to about 16 pF.
If I were to use single capacitors, then the bits in the counter (if I only use 4) will be as follows.
Bit 0: 1.2pF
Bit 1: 2.2pF
Bit 2: 4.7pF
Bit 3: 8.2pF
Here's the problem. When counting, I want to see:
1.2pF, 2.4pF, 3.6pF, 4.8pF, 6.0pF.... and so on.
According to the bits above, I would get:
1.2pF, 2.2pF, 3.4pF, 4.7pF, 5.9pF, 6.9pF, 8.1pF, 8.2pF.... and so on.
As you can see, the count is uneven.
Are there any better capacitor values that suit this application?
I want the even-most count without making my circuit consist of 99% capacitors.