# Electronic – the output voltage of this 555 timer high voltage circuit

555achigh voltagesimulation

I'm trying to calculate the theoritical output voltage of the following 555 timer high voltage circuit.
It claims to output up to 20kV, however results I get give only 12kV.

(source)

Here is how I did it:

According wikipedia, frequency in 'astable mode' is given by :

For this circuit :

\$f = \frac{1}{0,69 \cdot 0,00000001 F \cdot 33000\Omega} = 4391 Hz\$

I calculated the output of the transformer to be 125 times (1000 / 8) higher than input. Since 12v is given as input, output should be 1500v (not sure about this)

Then I draw the circuit in circuit lab:

simulate this circuit – Schematic created using CircuitLab

And I ran a time domain simulation (Stop Time = 30m, Time Step = 20u)

The output stabilizes at 12kV:

What is wrong? Did I miss something or are the results given by this circuit a little too optimistic?