HELP volts step down problem

i m attaching a circuit diagram which is step down the 220V AC to 7-8 A DC (AC?) can anyone explain the working of the 1 M ohm resistance and 1uF capacitor ,how they work and step down the voltage...
HELP volts step down problem

i m attaching a circuit diagram which is step down the 220V AC to 7-8 A DC (AC?) can anyone explain the working of the 1 M ohm resistance and 1uF capacitor ,how they work and step down the voltage...
MCB2300 3.3 and 5 volts on board

Dear All, I see in bottom to the MCB2300 (LPCR2378) and between INT0 button and buzzer the exits for 3.3V, 5V and GND. I have measured these exits (3.3 + GND and 5 + GND) with test multimeter but...
MCB2300 3.3 and 5 volts on board

Dear All, I see in bottom to the MCB2300 (LPCR2378) and between INT0 button and buzzer the exits for 3.3V, 5V and GND. I have measured these exits (3.3 + GND and 5 + GND) with test multimeter but...
wrting to BKPSRAM with 3.3 volts applied to v-bat

using the stm32f2xx_hal library I seem to be able to enable access to the BKPSRAM with __HAL_RCC_PWR_CLK_ENABLE(); HAL_PWR_EnableBkUpAccess(); __BKPSRAM_CLK_ENABLE(); Once this is done I can...