Here is a Neon Flasher circuit (untested) for a user request at Circuits FAQ. This can be built into a switchboard or a gadget for indicating Live Power.
D1-C1 form a simple half-wave rectifier, The Cap charges to peak voltage and can store charge for a long time if there is no bleeder. So while building it take extra care. This forms a DC supply across C1. C1 is a Plastic High-voltage cap, IN4007 has a 1KV rating, so it is ok for 230V rectifier.
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