5000VDC Output from 230 VAC Input, with Diode Voltage Multiplier / Capacitor

This High voltage power supply can generate voltage of 5000 volts DC from 230 Vac line voltage . Its main purpose is the production of negative ions.

WARNNG!
The explanations given here are for people who already have some knowledge about electronics, and should be fairly obviously. However, if you have any doubts, do not try anything! I am not responsible for problems resulting from improper handling! This refers to the elements connected directly to 230V which is very dangerous, and produces high voltage, which is not always dangerous, but still might be very shocking. Usual precautions apply before any intervention.

The diagram shows a set of cell diode / capacitor connected in series, each set of increasing voltage 300 V.
The voltage 230 V applied to the input of voltage multiplier, it gradually increased in each set of diodes / capacitors. Which eventually reached a value of more than 5000 V at the anode of the last diode (D16). Voltage rise gradually, as the capacitor discharged at the time of power up: voltage 5000 V was obtained after a few seconds.

Can we touch the test probes?
The fact that the assembly is connected to the line, then there is no issue of touching every part of the assembly either when connected to AC 230 V. That said, the tip should be exposed of negative ions diffusion outside the box which includes the installation, if the use of this system is very limited. What happens, then, if you touch the spikes carrying the potential of -5 kV? In fact, it was just a tingling, whose strength depends on the speed and force when pressing the points. The human body, is in fact the ohmic resistivity that behaves almost like a short circuit if the circuit is connected between ground and output, and in the case of direct contact, the output voltage collapses completely. This does not preclude that contact should not be very good (at the time of discharge the capacitor in the body), it depends on each person. Eight 2.2 Mohm resistor in series at the HV output reduces the output current in case of accidental contact. Note that the use of a single resistor of higher value is not recommended, because in the case of output short circuit, it will be applied to the terminal voltage is too high, an early time of if it does not break soon.

Can we measure the voltage output?
Yes, provided of course have a voltmeter that can support high input voltage. Think of the input resistance of the voltmeter, which combined with the internal resistance of the HV power supply, voltage divider formed a bridge, causing a voltage drop and the inevitable false readings (this is actually wrong if you trust them 100%). For example, if you use a needle voltmeter with input resistance of 20 ohms / volt, and the range is the range used 5 KV, the  input resistance of the voltmeter then 100 Mohm. This high internal resistance, but the internal resistance of the power supply is also high, the actual measured voltage can be as low as 3000 volts. With a digital voltmeter, the voltage reading should be between 4500 V and 5000 V. It is also possible to measure the electric field with a vacuum FET or gauge tube, the second solution may be preferred because of greater resilience (a FET can snap pretty quickly if the proposed electric field is too large, the tube on the other hand does not break).

Note : With a voltage of 5000 V, the air is not a very good insulator. Sparks can occur over a distance of several mm. It is therefore imperative that a minimum distance is maintained between the inlet and outlet of each cell multiplier. This minimum distance is 10 mm, well keep in mind when assembling the components!