Optimizing Sawtooth Wave Generator: Understanding Voltage and Amplitude

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In a sawtooth wave generator circuit, with Vcc at 15V, a voltage drop across Re of 2.7V, and a saturation point of Uce at 0.2V, the maximum voltage across the capacitor can be calculated as 12.1V. The transistor will enter saturation when the capacitor is full, but the circuit typically operates by discharging the capacitor before it reaches maximum amplitude. Adjusting the frequency of the impulses can influence the amplitude, but this is not the standard use of the circuit. Instead, the charging rate of the capacitor should be modified by adjusting R1 to achieve a desired frequency. This understanding confirms the correct approach to optimizing the sawtooth wave generator's performance.
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http://pokit.org/get/f118bc654187e429ec1bb489e1eb3a38.jpg

Suppose we have a sawtooth wave generator, like in the picture.

I have a fairly simple question:

If let's say Vcc is 15V, and let's say voltage drop across Re is 2.7V, and saturation point of Uce is 0,2 V. Provided that the period between impulses are long enough, what will happen when capacitor is full? Transistor will go into saturation right?

Or another way to put it, will my MAXIMUM(allowed) amplitude, or voltage across the capacitor be:

15-2.7-0.2=12.1 V?

And I can choose my amplitude by adjusting the frequency of those impulses?
 
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Yes, that is right.

That is not how this circuit would normally be used, though.

Ideally, the lower transistor's base would get a new pulse to discharge the capacitor just before the sawtooth wave reached maximum amplitude.

If you wanted to use a different frequency, then you would adjust R1 to give a different charging rate for the capacitor.
 
vk6kro said:
Yes, that is right.

That is not how this circuit would normally be used, though.

Ideally, the lower transistor's base would get a new pulse to discharge the capacitor just before the sawtooth wave reached maximum amplitude.

If you wanted to use a different frequency, then you would adjust R1 to give a different charging rate for the capacitor.

Understood. Thank you. Needed somebody to confirm my thoughts.
 
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