I've been trying to learn how to properly set up a circuit for power regulation. Often I hear for domestic use that it is better to use a transformer to isolate the device as well as stepping down the powerline voltage (230V RMS here). Seems pretty straight forward for lower voltages, but what about a heating element which is supposed to be supplied with 230V RMS? Is a 1:1 transformer still needed? If yes, is a 1:1 transformer and a LR8 regulator enough (obviously with some more passive elements and diodes) to generate a 5V (for a µcontroller for example), or will I need a second transformer?

If useful, the point is that my project will need 3 voltages: AC Line (heating element), about 15VDC (Peltier element), and 3.3/5VDC (µController, gates, fans, etc.).

The heating element is something like this.

  • \$\begingroup\$ You need to supply much more information. Most heating elements rated for 230VAC DO NOT have transformers ...think heating elements in a water heater ...a stove or oven element or an electric fire. You need to document the power levels your heater provides, how it's protected (from touch) etc. \$\endgroup\$ – Jack Creasey Feb 15 at 16:52
  • \$\begingroup\$ Done for the heating element. It's meant to heat air in a ~30x50x50cm box at about 30-60°C with a continuous confined airflow. \$\endgroup\$ – Kinxil Feb 15 at 17:16
  • \$\begingroup\$ I would suggest you DO NOT require a transformer for your heater. You will require isolation from your MCU controller, but that could be an opto-isolated Triac/SSR or a relay. You might need an isolated supply for your MCU/controller, but that depends on whether you can touch elements around it. For example, if your Peltiers are in the same power range (200W) you might use a small PC power supply to power them. That is isolated and provides 12V and 5V for your MCU. I've used cheaply available Xbox power supplies in this sort of application. \$\endgroup\$ – Jack Creasey Feb 15 at 17:30

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