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Topic: multiplier (Read 3 times) previous topic - next topic

domo


Here is a schematic for a possible solution. Since you still haven't said, I've assumed you are using the 5V version of the Q50 and that 8-bit resolution is sufficient. You will need to increase the PWM frequency if you want the settling time to be lower than a few seconds.


It is the 5V input version. Just checked.
8-bit is more than sufficient.

What coding specifically would go into arduino to control this?

dc42

Preferably, you should use PID controller software. There is a standard one for the Arduino. What method do you intend to use to select the output voltage? If the device will be standalone, then I suggest a rotary encoder and LCD display.

The 5.6V zener diode in the schematic is intended to limit the voltage fed to the Q50 to 5V. However, the datasheet for the Q50 implies that if you run it with 5V supply when the output is lightly loaded, it will produced more than 5kV, which is outside its safe operating area. Therefore, until you have got the software right (in particular, the PID parameters), I suggest you use a lower voltage zener diode (perhaps 3.9V or 4.7V) in order to limit the supply voltage to the Q50 to a lower value.

Here's a variation of the circuit that provides better current limiting and avoids the need for a power resistor. You should put a heatsink on the BD435 transistor.
Formal verification of safety-critical software, software development, and electronic design and prototyping. See http://www.eschertech.com. Please do not ask for unpaid help via PM, use the forum.

domo

The arduino will recieve data from matlab which measures the focus measure value from the lens. That part of the system has been done.
Depending on the value we need arduino to change the output voltage.

I still am unsure what the transistor does in the diagram.
Also the electro-optic lens needs the +/- ve connection, but on the diagram theres only one coming the hv multiplier.

dc42

The transistor passes the power (up to 250mA) to the HV multiplier. The op amp cannot supply enough current by itself.

The high voltage output is on the right hand side of the schematic. The positive side is marked "+ 0-5 kV", and the negative side is marked Gnd. The negative side is common with Arduino ground. If you wanted negative output instead of positive output, then you would need to use model Q50N and change the arrangement of the voltage divider.
Formal verification of safety-critical software, software development, and electronic design and prototyping. See http://www.eschertech.com. Please do not ask for unpaid help via PM, use the forum.

domo


The transistor passes the power (up to 250mA) to the HV multiplier. The op amp cannot supply enough current by itself.

The high voltage output is on the right hand side of the schematic. The positive side is marked "+ 0-5 kV", and the negative side is marked Gnd. The negative side is common with Arduino ground. If you wanted negative output instead of positive output, then you would need to use model Q50N and change the arrangement of the voltage divider.


Okay my bad, what i meant was that the lense has to electrode probes that would need the voltage going to. Can this just be divided from the output? I dont understand the 9V at the top section either.

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