Difference between revisions of "high voltage driver"

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Potential Transformers or Voltage Transformers are suited only for narrow applications. They are designed to measure circuits that can source a lot of current and operate at a fixed AC frequency and waveform, such as 60 Hz sine wave. (Note that these devices can often be run in reverse as good high voltage transformers).
 
Potential Transformers or Voltage Transformers are suited only for narrow applications. They are designed to measure circuits that can source a lot of current and operate at a fixed AC frequency and waveform, such as 60 Hz sine wave. (Note that these devices can often be run in reverse as good high voltage transformers).
  
A general purpose DC high voltage probe will typically be made from a resistor voltage divider. Many high voltage sources can drive only very low currents. Therefor the voltage divider must be very high impedance so as not to present a significant load. Resistances as high as 10000000000 Ohms (1e10 Ohms) may be required.
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A general purpose DC high voltage probe will typically be made from a resistor voltage divider. Many high voltage sources can drive only very low currents. Therefor the voltage divider must be very high impedance so as not to present a significant load. Resistances as high as 10000000000 Ω (1e10 Ω, or 10 GΩ, or 10 gigaohms) may be required.
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Fixed bandwidth AC High Voltage probes are made with a capacitive divider network.
  
 
Note that High Voltage High Frequency probes have different requirements than High Voltage Low Frequency probes. Remember, High Frequency does not imply AC. A pulsed DC voltage source may be High Frequency.
 
Note that High Voltage High Frequency probes have different requirements than High Voltage Low Frequency probes. Remember, High Frequency does not imply AC. A pulsed DC voltage source may be High Frequency.

Revision as of 13:13, 19 March 2014

 |                                           >             
gnd                                          >R1        
                                             >              
                                             |   
                                             |B        
                                            ---      GND 
           T1:NPN Power Transistor:2N3055  C/ \E     | 
                                           /   \     |
                                          | TVS |    |
                                      ----+->|<--+----+

TVS: This is a back EMF snubber. It may composed of a variety of components to suit. Sometimes you see zeners, or RC circuits, or transorbs (transient voltage suppression diode). Transil diodes provide high overvoltage protection by clamping action -- Part number 1.5KE15CA

A neon indicator bulb with a resistor in place of the TVS can be used to indicate when EMF is over 100 V.

Designing RC Snubber Networks

media:igbtAPPguide.pdf

Misc notes

L = N2 * p * A / l

  • L = inductance in Henrys
  • N = number of turns of wire (straight wire = 1)
  • p = permeability of the core material
  • A = are of the coil in square meters
  • l = average length of coil in meters.

Determine saturation by noting curve of values at different power levels. For example, determine when temperature sharply swings up as voltage or load increases.

Measuring High Voltage

Potential Transformers or Voltage Transformers are suited only for narrow applications. They are designed to measure circuits that can source a lot of current and operate at a fixed AC frequency and waveform, such as 60 Hz sine wave. (Note that these devices can often be run in reverse as good high voltage transformers).

A general purpose DC high voltage probe will typically be made from a resistor voltage divider. Many high voltage sources can drive only very low currents. Therefor the voltage divider must be very high impedance so as not to present a significant load. Resistances as high as 10000000000 Ω (1e10 Ω, or 10 GΩ, or 10 gigaohms) may be required.

Fixed bandwidth AC High Voltage probes are made with a capacitive divider network.

Note that High Voltage High Frequency probes have different requirements than High Voltage Low Frequency probes. Remember, High Frequency does not imply AC. A pulsed DC voltage source may be High Frequency.

More information

Samuel M. Goldwasser's Gadget FAQ with info on High Voltage