Circuit Lake

ESR (equivalent series resistance) is one of the characteristics that define the performance of an electrolytic capacitor. Low ESR is highly desirable in a capacitor as any ripple current through the capacitor causes the capacitor to heat up due to the resistive loses. Typical capacitor checker measures the capacity of the test capacitor. Some advanced [...]

This simple analog electronic circuit can detect the presence of 13.56 MHz RFID tags that used by all plastic cards like access badges, bank cards, library cards, loyalty cards. Also many other objects like books, toys, or clothing that may carry RFID tags without you knowing it.

Here is the most stable, smallest, and energy saving FM transmitter. It uses only single transistor oscillator, PN2222A. Other high frequency / low noise transistor like 2N2222A, BFxxx series, BC109B, C, and even well known BC238 could work as well. Key to a well functioning, low consumption circuit is to use a high hFE / [...]

This mini LED flashlight is very useful for emergency use. Since it size is small enough to put in your pocket, you can bring it anywhere. This portable LED flashlight is powered by only one AAA battery. To boosting input voltage (1.5V) up to operating voltage of a super high luminosity LEDs -blue, green or [...]