IC engine spark plug voltage tester with flashing indicator - has conductor on cable insulation, forming capacitor with cable core and being in electric contact with tester and operator

摘要

The electric power required for the operation of the flashing voltage tester is obtained by securing a conductive element on the insulation of the ignition cable. The conductive element is secured to the cable permanently, or during the testing only. This element forms with the cable core a capacitor and is also connected to the voltage tester and to the person carrying out the test. The slight electric energy is rectified and accumulated. When the energy has reached the ignition voltage for a glow lamp, the capacitor is discharged across this lamp. The discharge frequency is determined by the ignition voltage and frequency.