[introduction] the voltage that provides stable dynatron base with stabilized voltage, this voltage course launchs knot clamp later reduce 0.7V, blast off right now extremely voltage also is stability, blast off extremely voltage is divided in order to blast off extremely resistor has to arrive constant electric current. If pursue, load is received in red point point, load current is constant for 5mA.

Share a few kinds of forms that take constant current cause with dynatron today.

Cooperate stabilized voltage canal to take constant current cause

With stabilized voltage the canal stabilizes the voltage of dynatron base, this voltage course launchs knot clamp later reduce 0.7V, blast off right now extremely voltage also is stability, blast off extremely voltage is divided in order to blast off extremely resistor has to arrive constant electric current. If pursue, load is received in red point point, load current is constant for 5mA.

Blast off through adjusting extremely it is OK to resistor block is worth or change the stabilized voltage that is worth with different stabilized voltage to be in charge of the adjustment that realizes load current size.

Galvanometer calculates formula:

Cooperate source of diode constant current

With two diode clamp, stabilize base voltage 1.4V. The analysis of the others and stabilized voltage valve are same.

No matter be to cooperate stabilized voltage canal or diode to take constant current cause, their principle is same, we should dig disinter marrow to come out, in the future encounters ability of picture of this kind of principle to accomplish draw inferences about other cases from one instance, the marrow that constant current designs here stabilizes the base voltage of dynatron namely! Because be passed after stable base voltage,shoot extremely clamp, repass is shot extremely the electric current with the voltage stable translate into with will stable resistor, realized constant current so!

Their general galvanometer calculates formula to be as follows:

Mastered stable base voltage this principle, can extend an a lot of constant current to design circuit, perhaps do a referenced voltage for instance with TL431 with DA, perhaps use 3 diode pincers OK!

Oneself are OK after summary gives marrow from imitate change proper motion to the design, this kind of feeling is very cruel!

Two dynatron take constant current cause

Come to again different, by the constant current source that two NMOS make.

Say my understanding to this circuit: This is constitutionally actually shed protective circuit too.

Dynamic process

Base electric current is passed, right canal is opened, after magnifying electric current, be more than 0.7mA when load current, blasting off extremely 0.7V voltage is formed to achieve left canal to guide on resistor a threshold value, left canal open.

Left canal open, right canal base is pulled the ground, bring about right canal to shut.

Right canal is shut, did not have base of voltaic left canal to be pulled the ground, bring about left canal to shut again,

Left canal is shut bring about right canal to open again.

Move back and forth circulates, dynamic and stable moment is left canal base voltage achieves 0.7V of enlightened threshold value, this is a balance dot.

This process is a bit complex still, look not to understand to also have nothing to do with so, can so will understand: Two dynatron are in guide the balance issues a trends that closes, pipe base equivalent is in into stability on the right side of 1.4V, shoot extremely stable 0.7V, also can mix so above those who sum up the marrow that come out to also have different in approach but equally satisfactory in result became clever.

Voltaic computation is formulary and OK so direct calculate:

Said I think this is one sheds protective circuit too in front, base electric current wants enough big, after magnifying through right canal, can blasting off extremely 0.7V pressing is formed to fall on resistor, this process ability holds water. Next dynatron is a dynamic resistor with respect to equivalent, make laden constant current! If Ib is very small, through after right canal magnifies, cannot be being formed 0.7V pressing falls, so this process does not hold water.

Above is him the view to these a few circuit and summary. Because the level is finite, presumable place understanding has by accident, if have,discover an error, still ask point out mistakes so that they can be corrected of each not stint! Acknowledgment!

Want to nod summary:

1. dynatron builds marrow of constant current source to depend on stabilizing base voltage.
Knot clamp blasts off after 2. stabilized base voltage, blast off extremely voltage is stable also.
3. is passed blast off extremely translate into of voltage of resistor general stability is constant electric current.

(author: Hoof of leg wool big pig)

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