This simple alarm with thermostats circuit can be used on places where we must detect overheating. It uses 3 thermostats, and a one, 2 contact, relay
Apr 102018
Apr 052018
12V Auto turn-off battery charger
This 12V auto turn-off battery charger automatically disconnects from mains to stop charging when the batteries are fully charged. It serves to charge the battery of our car, using the 120/240 VAC
Apr 042018
Transformerless Power Supply Circuit We will use a zener diode among other elements to acheive the Transformerless Power Supply circuit. This means that our power supply will give a limited range current value (it will be a maximum and a minimum posible current that the power supply circuit can deliver). This power suply must be permanently connected to the circuit as a whole […]
Apr 032018
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
Apr 022018
NAND gate using transistors
This NAND gate using transistors circuit simulates the operation of a two or more inputs NAND gate. (There is a diode for each input. D1, D2, …)
Mar 282018
Car battery monitor circuit using 4 LEDs
This simple Car battery monitor, allow us to know the voltage of the battery at all times. To achieve this 4 leds are placed somewhere on the dash of the car. Each LED has a label indicating the battery voltage at that time.
Mar 272018
TRIAC. Power control on alternating current (AC)
Triac is a semiconductor device that belongs to the family of thyristor control devices. It is essentially two SCR connected in parallel and backwards, sharing the same gate.
Mar 262018
8 LED VU meter made of IC-LM324.
This circuit can be used to display the variation of an audio signal in a group of 8 LEDs, behaving like a VU meter. We could use an specific integrated circuit used for VU meters, but we decided to use a readily available integrated circuit: The LM324 op amp.
Mar 252018
OR and AND logic gates made with diodes
The Diode Logic uses the fact that the diodes conduct only in one direction. (they behave like switches)
Feb 042018
Water Level Controller Circuit
This simple Water level controller circuit is useful to control the water level in a tank. It does this by turning On and Off a water pump depending on the status of the sensors.
Jan 162018
This rain detector using two transistors, is a simple circuit that aims to alert the beginning of the rainfall.
The applications for this circuit can be many, but the most obvious is to alert people who have their clothes drying under the sun or the wind, to put them under the roof before they get wet again.
Dec 092017
UJT or Unijunction transistor
The UJT or Unijunction transistor is constituted by two polluted regions, with three external terminals: two bases and one emitter.