A phototransistor is essentially the same as a common transistor, but it can work in two different ways:
– As a common transistor, using the base current (IB)
– As a phototransistor, using the light that illuminates this element and that acts as the base current. (IP).
DC motor speed controller circuit using 555
This simple DC motor speed controller circuit, works with 12 volts and controls a DC motor using the 555 integrated circuit.
400 watts Stereo Amplifier Circuit using STK4050
This 400 watts stereo amplifier circuit uses the Sanyo STK4050 hybrid IC, a high quality low noise amplifier. Its maximum output power is 200W per channel
Refrigerator door alarm circuit with two 555 timers
This refrigerator door alarm circuit alerts you when the door has been left open. Very important, because the power consumption increases when this happends. It uses the popular 555 timer IC
This 2 LED Temperature change indicator shows us, by means of two LEDs, when the sensed temperature is above or below a set limit.
When the temperature is above the pre-set temperature level, LED D1 will light up and if it is below, LED D2 will light up.
What is a Zener diode?
The Zener diode is a special type of diode that allows the flow of current on the opposite direction of the arrow of the diode. This diode does not conduct until the applied voltage reaches or is greater of the breakdown voltage. Zener diode is very popular as Voltage reference element.
Power Factor Definition
Power factor is the ratio between the energy that is converted into work and the electrical energy consumed in a circuit or device
Tone generator using two 555 timers
This circuit uses the well-known 555 integrated circuit to generate a range of sounds that are heard through a small loudspeaker.
Ohm’s Law relates in one equation the voltage, the current and resistance. Resistance = Resistor’s value.
A more complete expression of Ohm’s Law is achieved using the electric power formula
Water level controller circuit using CD4001
This water level controller circuit controls the level of water in a tank. Unlike mechanical controls using a floating buoy, this circuit uses two sensors, an upper sensor and a lower sensor,
Fuel Pump Cut-off Circuit
Fuel pump cut-off circuit for the car prevents the activation of the pump. Useful to increase the security level of a car which already has an alarm installed
Audio level indicator circuit using LM339
This audio level indicator is very interesting because it allows us to visualize the audio level intensity by connecting this circuit to the input of a loudspeaker.