NOR logic gate
A NOR logic gate can be implemented with the concatenation of an OR gate and a NOT gate. NOT gate using a NOR gate
Jun 192017
Jun 102017
This Electric Current Flow Indicator gives a visual indication that there is a current flow. Possible applications for this small circuit may be: a battery charger, a voltage power source, etc.
In order to achieve our objective we place 3 rectifier diodes in series, which in turn are in series with the load / battery.
Jun 092017
This High – Low Temperature 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.
Jun 082017
Astable multivibrator using NAND gates
This astable multivibrator uses two NAND gates of the 4 available on the 7400 TTL integrated circuit. Two LEDs are used to view the status or logic output of each gate.
May 312017
Logic Probe using NOT Gates (Inverters)
This logic probe using NOT Gates is implemented with three NOT gates, one rectifier diode, two LEDs and two resistors.
May 222017
Time Delay circuit using Triac and 555 timer
This Time delay Circuit using Triac and 555 Timer is very useful when we want to activate or switch on, appliances or devices that works on alternating current (AC), after a preset time.
Apr 062017
Car Burglar Alarm using two 555 timers
This is a simple Car Burglar Alarm circuit that uses a dual contact relay and two 555 timers, each of them working as a monostable multivibrator.
The alarm will activate the car horn, approximately 5 seconds after either door is opened and has not been properly closed.
Apr 042017
1 Input – 4 Outputs Stereo Audio Splitter
This 1 Input – 4 Outputs Stereo Audio Splitter has a single input and 4 independent outputs, each amplified with an operational amplifier.
Each operational amplifier is configured as an emitter follower, to take advantage of its high input impedance and low output impedance, thus avoiding distortion in sound.
Apr 032017
20 Amp Variable Power Supply using LM317
This 20 Amp Variable Power Supply varies its output voltage from 1.5 to 15 volts and is based on the well-known variable voltage source configuration, where only the LM317 voltage regulator is used.
Mar 282017
Audio level indicator using LM339
This audio level indicator using LM339 circuit is very interesting, because it allows us to visualize the audio level intensity by connecting this circuit to the output of a loudspeaker.
The LM339 integrated circuit has 4 comparators that operate completely independently but share the same voltage source.
Mar 212017
Logic point using 7 segment display
This logic probe with 7 segment display is designed with TTL technology and does not use LEDs to display the high and low logic levels found in many of the logical probes on the market. The circuit shows the capital letter “H” when there is a logical “1” or the letter “L” when there is a logical “0”.
Mar 142017
Two Transistor Logic Probe
This Two Transistor Logic Probe is a very simple circuit that can be implemented using two NPN bipolar transistors (T1, T2) in a Darlington configuration.