Senin, 14 Desember 2009

Day 11 .. CCS anyway part 1.

Day 11.

Amazing ... I've been here for 11 days, still lost in hole and still figure it out what am I doing here.
CCS stands for a Constant Current Source. This means the current through
the device is constant no matter what the voltage across the device does.
(That is until you blow it up.)

A CCS can be made to deliver a constant current from DC on up to very high
frequencies or they can be made to look like a resistor at DC and turn to
constant current between 0.1 to 100 Hz (sort of like an inductor). Some
people call the ones that are a resistor at DC an "active load." I lump
them both under CCS's.

A big thing is a CCS on the plate of a tube requires a higher B+ than a
tube with an inductor on the plate. A CCS on the plate of a tube can operate
with the same B+ when the tube has resistor on the plate for bias.

In my book, a good CCS always sounds better than a resistor for bias. A
goodCCS usually sounds better than a typical inductor.

--- End of the simple explanation, on to the details. ---
--- Al, you may not be happy if you keep reading ;-] ---

Detailed characteristics of an inductor:
1. Can swing voltages above B+.

2. DC series resistance causes the B+ to need to be a bit higher to bias
up the tube.

3. Has AC parallel resistance (that varies with voltage and frequency)

4. Has AC parallel capacitance that can affect the load line at high
frequencies. This capacitance is fairly flat in value with voltage and

5. Inductance (impedance = j * 2 * pi * frequency * L). The inductance
varies with voltage and frequency causing the impedance to vary with
voltage and frequency.

6. The inductance will vary with current and can drop to zero at too high
of a current.

7. An inductor usually has enough surface area that it cools itself
without needing added heat sinking.

8. An inductor suffers from magnetic coupling (both in to and out of the
part) with adjacent iron

9. An inductor can suffer from capacitive coupling (in and out again) with
adjacent parts and wiring.

10. An inductor can be sensitive to vibration.

11. Has a fairly well defined transient response

12. Generates current distortion that when multiplied by the plate
resistance of the tube, turns into a voltage distortion.

to be continue ....... mbuh kapan.

Tidak ada komentar: