Some safety/tools in AC mains power Switch Mode Power Supply '(SMPS) Troubleshooting and Repair'. A residual-current device (RCD), residual-current circuit bre

Some safety/tools in AC mains power Switch Mode Power Supply '(SMPS) Troubleshooting and Repair'. A residual-current device (RCD), residual-current circuit breaker (RCCB) or ground fault circuit interrupter (GFCI) : https://en.wikipedia.org/wiki/Residual-current_device https://en.wikipedia.org/wiki/Residual-current_device (1:1) Isolation Transformer : https://en.wikipedia.org/wiki/Isolation_transformer https://en.wikipedia.org/wiki/Isolation_transformer Autotransformer : https://en.wikipedia.org/wiki/Autotransformer https://en.wikipedia.org/wiki/Autotransformer 'series incandescent light bulb(s) current limiter'