Electronic Circuits and Diagram-Electronics Projects and Design

Description. A timer circuit using IC 4060 is given here. The IC 4060 is a 14 stage binary counter with a built-in oscillator.R2, R7, C1 are the components that determine the frequency of the oscillator and the outputs will become high one after other and only one at a time. The last five outputs are only used here. The high pulses from the outputs are used to trigger the NE555 IC. Here NE555 is wired as a monostable multivibrator. The buzzer will produce the alarm when the output of IC2 goes high. The duration of the alarm depends on the…

Description. The circuit given here is designed as an LED flasher which produces a rotating effect when the LEDs are arranged properly. The circuit has very low current consumption and can be operated from even 3V button cells. The IC 1 (CMOS NE555) is wired as an astable multivibrator wired at a duty cycle of 50% and 4Hz frequency and drives LEDs D1 to D6.The second IC, IC2 (CMOS NE555) is working as a trigger pulse inverter and drives LEDs D7 to D12.The circuit is arranged such that the ICs sink the current consumed by the LEDs. At low operating…

Description. The circuit given here can be used for tossing head or tail. There are many games in which a tossing is required to start and this circuit can be used in all such instances. The circuit uses two ICs NE 555 timer (IC1) and 74LS76 dual JK flip flop (IC2).The IC 1 is wired as an astable multi vibrator operating at 10Hz.The output of IC1 is inverted by using the transistor Q1.The collector of Q1 is connected to the pin 1 of IC2 via the push button switch S1.The IC2 is wired in toggle mode. When push button S1…

Description. This is a simple circuit that can be used as a sequential signal light in automobiles. The circuit is based on two ICs. A TS 555 CN CMOS timer IC and a CD4017 decade counter IC. The IC1 is wired as an astable multivibrator to trigger the counter IC. When triggered, the outputs of the IC 2 (pins 3, 2, 4 and 7) will go high and low in sequence and the speed of this sequencing will be proportional to the triggering frequency. The transistors Q1 to Q4 drives the corresponding LEDs. The switch S1 can be used to…

Description. This circuit was designed in response to a request from my reader. What he asked for was a 1KHz IR transmitter circuit for some remote control application. I think this circuit may satisfy him. Any way this circuit can be used where ever a low power IR transmitter of 1 KHz operating frequency is needed. This transmitter can transmit up to a distance of about 10 meters. The circuit is based on a NE555 timer IC (IC1) which is wires as an astable multivibrator to produce 1KHz pulses. The output pulses of the IC1 will be amplified by the…

Description. The dark detector circuit shown here can be used to produce an audible alarm when the light inside a room goes OFF. The circuit is build around timer IC NE555. A general purpose LDR is used for sensing the light. When proper light is falling on the LDR its resistance is very low. When there is no light the LDR resistance increases. At this time the IC is triggered and drives the buzzer to produce an alarm sound. If a transistor and relay is connected at the output (pin3) of IC1 instead of the buzzer, electrical appliances can be…

Description. When ever you need to get an alarm or intimation after ten minutes ,the circuit shown below can be used.The circuit is nothing but  a monostable multivibrator based on IC NE 555.When ever you press the reset push button the green LED D1 glows after 10 minutes. Circuit diagram with Parts list. Notes. Assemble the circuit on a good quality PCB or common board. The time duration can be set by varying the POT R5. The switch S1 can be a push button switch. The IC1 must be mounted on an IC base.

Description. The main part of this doorbell circuit are two NE555 timer ICs.When some one presses switch S1 momentarily ,the loud speaker sounds a bell tone as long as the time period of the monostable multivibrator built around IC1. When the switch S1 pressed, IC1 is triggered at its pin 2 and output pin 3 goes high for a time period previously set by the values of POT R4 and POT R5.When the output ofIC1 goes high it resets IC2 and it starts to oscillate to make a bell sound through the speaker.The IC2 is configured as an astable multivibrator…

Description. An NE555 timer IC connected as shown here can detect a missing pulse or abnormally long period between two consecutive pulses in a train of pulses. Such circuits can be used to detect the intermittent firing of the spark plug of an automobile or to monitor the heart beat of a sick patient. The signal from the pick up transducer is shaped to form a negative going pulse and is applied to pin 2 of the IC which is connected as a mono stable. As long as the spacing between the pulse is less than the timing interval,the timing…

Description. Apart from the timing functions ,the two comparators of the 555 timer can be used independently for other applications.One example is a Schmitt Trigger shown here. The two comparator inputs (pin 2 & 6) are tied together and biased at 1/2 Vcc through a voltage divider R1 and R2.Since the threshold comparator wil trip at 2/3 Vcc and the trigger comparator will trip at 1/3Vcc,the bias provided by the resistors R1 & R2  are centered within the comparators trip limits. By modifying the input time constant on the circuit,reducing the value of input capacitor (C1) to 0.001 uF so…