Regulated power expander circuit
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... read moreVoltage booster circuit
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... read moreMains failure alarm circuit
 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... read moreHigh & Low voltage cut-off with delay& alarm
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... read more9 V regulator using 7809
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... read more5V power supply using 7805.
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... read moreTransformerless Power Supply Circuit
Transformerless power supply Circuit 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 will regulate the filtered DC and will keepthe voltage steady at 5V. You may also like: Transformerless Switch Mode Power Supply Transformerless Power Supply Circuit Diagram with... read more6 Volt regulator circuit using 7806
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. 7806Â 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. 6 Volt Regulator – Parts List Voltage Regulator... read more