Abstract: Apparatus (2) for electrically charging liquid droplets for use in the stimulation of plant growth and/or the control of insects, which apparatus (2) comprises spray means (16,18:20,22) for spraying at least one spray of liquid from the apparatus (2), and electronically operated liquid-charging means (12) for causing the liquid to be electrically charged in such a manner that liquid droplets constituting the spray are able to retain their charge until earthed during use of the apparatus (2).

Abstract: Ignition apparatus for providing plasma ignition for an engine, which ignition apparatus comprises a switching circuit, a wave form generator for generating an a.c. wave form output, a power amplifier circuit for amplifying the output from the wave form generator, a d.c. to d.c. inverter, and a transformer having primary and secondary windings, the primary winding being connected to the power amplifier circuit for receiving the output from the power amplifier circuit, and the secondary winding being connected to the d.c. to d.c. inverter, and the wave form generator and the d.c. to d.c. inverter being connected in parallel so that during operation of the ignition apparatus high voltage a.c. from the wave form generator carries and sustains d.c. which is from the d.c. to d.c. inverter and which is required for the plasma.