Category Archives: Circuit Diagram

[Multi-Colour] Automatic Night Lamp Circuit Diagram Using LDR And CD4017

Automatic Night Lamp Circuit Diagram Using LDR And CD4017 Components Required: Resistors (All 1/4W)R1 – 220ER2 – 1M(Preset)R3 – 33K LEDs:(3m/5mm/8mm)L1- WhiteL2- YellowL3 – GreenL4 – BlueL5 – Red Transistor:Q1 – BC547Q2 – 8050 or SL100 IC:U1 – CD4017 LDRMomentary Switch (Push to on)PS – Power source 12VGeneral purpose PCB Nіghtlіghtѕ are uѕеful to show thе gеnеrаl lауоut оf a rооm without […]

Burglar Alarm Using NPN(BC548)And PNP(SK100) Transistor

The burglar alarm circuit shown here sounds an alarm when the wire loop is broken.The system is implemented by installing a sensing loop, which is basically a thin copper wire. This way, the loop is both invisible and brittle enough to break easily and initiate the alarm mechanism.At the time of an intrusion, the loop […]

SIMPLE AUDIO ALARM CIRCUIT USING BC547 AND S8550

Parts Required: Capacitors C1 – 0.02uF ceramic disc C2 – 1000uF, 12V or 25V Resistors (All 1/4Watts) R1 – 100K R2 – 2.2K R3 – 47E Transistors T1 – BC547 (NPN) T2 – S8550 (PNP) Loudspeaker – 8 ohms Battery – 9V This is a simple audio alarm which operates from 3 to 9 volts and […]

20 Led Chaser Circuit Without Ic 555 | How To Build A Light Chaser Circuit Using Cd4017 And Cd4013

20 Led Chaser Circuit Without Ic 555 | How To Build A Light Chaser Circuit Using Cd4017 And Cd4013

This is a simple 20 led chaser circuit built using the decade counter ic CD4017 and Dual flip flop ic CD4013. CD4017 is wired as divide by 10 counter. One flip-flop of CD4013 is wired as multivibrator and another flip flop is wired as divide by 2 counter. Output pin 2 from CD4013 is connected […]

Simple Battery Monitor Circuit Diagram Using NPN Transistor BC547 | Car Battery Monitor Circuit

Parts Used:Transistor : BC547 (Q1)Resistor (All are 1/4Watts)R1 – 10KR2 – 1KR3 – 1K Diode:D1 – 6V, 500mW ZenerD2 – LED (any color)Circuit Description:This circuit indicates a warning whenever the battery voltage falls below the level set by 10K pot. It can indicate that the battery is defective or needs charging if cranking drops battery voltage below preset “safe” […]

12V BATTERY LEVEL INDICATOR USING LM3914 | BATTERY LEVEL INDICATOR CIRCUIT DIAGRAM

Part Used:IC:U1 – LM3914 Resistors (All 1/4 watts)R1 – 4.7KR2 – 4.7K (preset to set upper limit)R3 – 1.2KR4 – 4.7K (preset to set lower limit – 10.5V) Circuit Description:The LM3914 acts as a LED driving voltmeter that has its basic maximum and minimum readings determined by the values of R1 and R2. When correctly adjusted, the unit actually […]

Low Battery Level Monitor Using Op-Amp 741

Parts Used: Resistors: (All are 1/4 Watts) R1 – 1M R2 – 470K R3 – 8.2K R4 – 680E Diodes: D1 – 5.1 Zener (500mW) D2 – IN4148 L1 – LED (any color) IC: U1 – Op-Amp 741 Battery: BT1 – 12V Switch – On/Off Circuit Description: A 741 op-amp is employed as a voltage […]

12V Battery Charge/Discharge Indicator Using The Dual Op-Amp LM358 | 12v battery level indicator

Parts Used: Resistors: (1/4 Watts) R1 – 10K R2 – 10K R3 – 10K (preset) R4 – 10K (preset) R5 – 1.5K R6 – 1.5K R7 – 1K R8 – 1.5K R9 – 1.5K IC: U1 Dual Op-Amp LM358 LEDs: Red Green Yellow Fuse:100mA 12V Battery General purpose PCB Circuit Description:This circuit monitors the 12V battery […]

BATTERY LOW LEVEL INDICATOR USING TIMER IC 555 | LOW BATTERY INDICATOR CIRCUIT 12V

Parts Used: IC: U1 – 555 Timer Resistors (All 1/4 Watts): R1 – 22K R2 – 8.2K R3 – 470E Capacitor: C1 – 0.001(ceramic disc) Diode: D1 – 6v, 500mW (Zener) LED – Any color 12V Battery Circuit Description: The average current drain is 1mA or less due to the low duty cycle of the […]

Water Level Indicator Circuit Project Using IC 555 With Motor Dry Run Protection Alarm

Components Required:Resistors (All 1/4W)R1 – R6 – 1MR7 – R12 – 220KR13 – R17 – 1KR18 – 3.3KR19 – 1MR20 – 100K (Preset)R21 – 1KR22 – 1.5K Capacitors:104(0.1uF) – Ceramic Disc – 1 no.100uF,25V – 1 no.470uF,40V – 1 no. IC:U1- CD4049 (with Base)U2-555(with Base) Diodes:D1 – LEDD2 & D3- IN4148DB1- W04 (Bridge Rectifier) Transistor:S8550 PNP Relimate Connector:Sensor – […]