This simple circuit indicates the amount of power that goes to a loudspeaker. The dual-colour LED shows green at an applied power level of about 1 watt. At 1.5 watts it glows orange and abov... Read more
This circuit was designed as a warning flasher to alert road users to dangerous situations in the dark. Alternatively, it can act as a bicycle light (subject to traffic regulations and legis... Read more
This device is designed to be a simple, inexpensive ‘comparator’, intended for use in a solar cell power supply setup where a quick ‘too low’ or ‘just right’ voltage indicator is needed. The... Read more
This simple circuit can be used to activate whatever you like, for example, by connecting it to microcontroller, relays, secret alarms, robot applications or just turn on LED1 which lights u... Read more
This is a reaction timer game between two players, red and green. Each player has a pushbutton in front of him that he must press at just the right moment: not too early and not too late. Th... Read more
If you forget to switch off the light after leaving a seldom used room (such as the loft), there’s a strong likelihood that it could remain lit for months, running up an expensive power bill... Read more
This simple LED tester consists of a current source with a potentiometer that can be used to adjust the current. The current source is implemented using a type TL081 opamp. The output curren... Read more
For several years now, a rear fog lamp has been mandatory for trailers and caravans in order to improve visibility under foggy conditions. When this fog lamp is switched on, the fog lamp of... Read more
As we all know, LEDs are dimmed by altering the current flowing through them, not the voltage. We achieve this effect in this circuit by using an AVR microcontroller (2313 from Atmel) operat... Read more
Here we couple LED oscillators together to produce some interesting effects for an exclusive optical touch to your robot. As seen in the circuit diagram in Figure 1, instead of using the dis... Read more
