Electronic Circuits and Diagram-Electronics Projects and Design

Description. Commercially available voltage regulator IC’s can deliver up to 1A output current. For example 78xx series regulators are available in different voltage ratings, but in any case the current should not exceed 1A. The transistor Q1 (2N 29055) used here has 5A current capacity. The resistor R1 is used to keep the current through regulator IC below 300mA. When the current through R1 increases the base current of Q1 (2N 29055) also increases &the load required load current flows through this transistor. By this way a current greater than the capacity of the regulator IC can be delivered to…

Description.  Here is a simple circuit for boosting 12 V DC to 24 V DC .The circuit is designed straight forward and uses few components.With few modifications the circuit can be used to boost any voltages. The transistor Q1 and Q2 (D1616)  essentially drives the primary of the transformer.The diodes rectifies the output of transformer to obtain a 24V DC at the output load(here a fan).The capacitors filter away noise and harmonics away from the output. Circuit diagram with Parts List.  Notes.  The component values are not very specific here.We can use any NPN power transistors like D1616,2N 3055,C2236,SL 100…

 Description. Here is a simple mains power failure alarm/detector circuit that produces an alarm whenever the mains supply fails. Lot of such circuits are available, but the peculiarity of this circuit is that it requires no back up power source like a battery to power the alarm when the mains is absent. When there is mains supply the transistor Q1(BC558) will be OFF and the capacitor C1 will be charged. When the mains supply fails the transistor Q1 becomes ON and the capacitor C1 discharges through the Q1 to drive the buzzer to produce an alarm. The capacitor C2 is…

Description. This straight forward circuit will protect electrical appliances from over voltage as well as under voltage. The circuit also produces an alarm when the power supply comes back. An ideal circuit for home to protect your valuable equipments from voltage fluctuations. The same circuit with some modifications can be used  to make a automatic voltage stabilizer. When the mains voltage is in the normal level, the voltage at the negative terminal of zener diode D4 will be less than 5.6 Volts. At this condition transistor T1 will not conduct. The same time voltage at the negative terminal of zener…

Description. Here is the circuit diagram of 9 V regulator using popular 7809 IC. The 7809 is a 9 Volt voltage regulator IC with features such as internal current limit, safe area protection, thermal protection etc. A 16 V transformer brings down the 230V mains, 1A bridge rectifier rectifies it and capacitor C1 filters it and 7809 regulates it to produce a steady9V DC  output. Circuit diagram with Parts list.  Notes.  If a current of 300 mA or above is required, fit a proper heat sink to the IC 7809. If 1A bridge is not available, make one using four…

Description. 7805 is a 5V fixed three terminal positive voltage regulator IC. The IC has features such as safe operating area protection, thermal shut down, internal current limiting which makes the IC very rugged. Output currents up to 1A can be drawn from the IC provided that there is a proper heat sink. A 9V transformer steps down the main voltage, 1A bridge rectifies it and capacitor C1 filters it and 7805 regulates it to produce a steady 5Volt DC. The circuit schematic is given below. Circuit diagram with Parts list. Notes. The bridge D1 can be also made by…

Transformerless power supply Description. Here is a low cost and simple circuit that can be used to power up small electronics devices. The power is directly tapped from the mains via resistor R1.D1 rectifies the voltage and C1 and C2 are used to filter the output.The zener diode D2 keeps the voltage at steady 5V. Transformerless Power Supply Circuit Diagram with Parts List.   Notes. This circuit can deliver only up to 2omA ,there fore not suitable for serious circuits. You can use this power supply for small LED circuits etc . Remember you are playing with mains.Always be careful…

6 Volt Regulator using IC 7806 Description. Here is the elementary 6V 1A power supply circuit using 7806 IC. The 7806 three-terminal positive voltage regulator is available in the TO-220/D-PAK package making them useful in a wide range of applications. 7806  employs internal current limiting, thermal shut down and safe operating area protection, making it essentially indestructible. If proper heat sinking is provided, it can deliver over 1 ampere output current. Voltage Regulator Circuit Diagram with Parts List . Pin out of 7806 Notes . If 2A bridge is not available make one with four 1N 4007 diodes. Fit a…

Power Supply Circuit-40 Volts-2A Description. This is a power supply circuit diagram of 40Volts, that is able to deliver 2A current.This circuit is suitable for power amplifiers .Transistor TIP 42 A is used as a pass transistor to increase the current capabilities.Voltage regulator LM 317 is the heart of this circuit .Here the out put voltage is set to 40 V by R5 & R8.If you want any other out put voltage use a 10 K pot instead of R5 and adjust it. Parts List. R1_______________3R9 1 or 2W Resistor R2______________   22R  1/4W Resistor R3_______________6K8 1/4W Resistor R4_____________     220R  1/4W…

Dual Adjustable Power Supply Circuit Description This is the circuit diagram of a dual adjustable power supply using IC’s LM 317 & LM 337.LM 317 is able to deliver a maximum of 1.5 A at a range of 1.2 V to +30V .LM 337 is the negative complement of LM317.They also have a built in short circuit protection. Here the circuit is wired to produce a dual adjustable output of ( +15 , 0 , -15 ).The capacitors C1 to C8 provides filtering and ripple rejection.Resistors R1 & R2 controls output of LM 317.Resistors R3 & R4 controls the output…