Simple circuits

If you make a device with external RTC module this essay can help you to make simplest backup powering (reverse power) using coin cell battery.

Load switches are used for power control of any loads, typically it's used to fully enable or disable power of integrated circuits (chips) to achieve low power consumption in sleep mode.

Here is simplest high-side load switch on discrete components, that can be used instead of special ICs. Firstly some work simulation in MicroCap and then real testing with board.

Utterly simple and useful circuits for protect your device against incorrect power supply polarity (reverse polarity) connection:

• High Side (based on P-Channel MOSFET)
• Low Side (based on N-Channel MOSFET)

This really simple thing can save the life of your electronic device, without taking up much space, thanks to modern miniature transistors.

Simplest blinking circuit, implemented in small board with convenient mounting hole.