Sound-to-Beep Circuit using IC CD4049 is a fun project. Hear whistle which beep for 3 sec. Circuit is good for door alarm, remote control other sound things. It has mic for sound, op-amps from CD4049 and transistor for buzzer. It runs on 3V battery. Circuit Working: Parts List: Component Type Value Quantity Resistors (All resistors […]
Simple Dark Sensor Circuit for Security using IC 555 timer
Simple Dark Sensor Circuit for Security using IC 555 timer is useful project for security. It senses low light and turns ON the buzzer or light. It is used for LDR as light sensing. Circuit is good for night light and alert system. The circuit have parts like 555 IC, LDR, resistors, capacitor and buzzer […]
USB Lamp Circuit for Portable Lighting
USB Lamp Circuit for Portable Lighting is good for portable light. It is easy to use and takes power from USB port of 5V. It have rechargeable battery which are more useful. USB port give only 100 mA so use LEDs less. Circuit have transistor, diodes, capacitor, resistors, LEDs for good light. Circuit Working: Parts […]
Dual LED Temperature Indicator Circuit
Dual LED Temperature Indicator Circuit light one LED when hot and other when cold. It uses IC LM35 temperature sensor, CA3130 op-amp and two BC547 transistors. IC 7805 change 9V to steady 5V and if there is 5V already then we can connect directly. IC LM35 gives 10mV more for every 1°C rise. Output goes […]
Headphone Amplifier Circuit using Transistors
Headphone Amplifier Circuit using Transistors make weak sound strong so headphones work well. This circuit is useful when sound is direct from source which is not loud or clear. In this post we talk about small 3V transistor amplifier for better sound. Circuit Working: Parts List: Component Type Value/Specification Quantity Resistors (All resistors are 1/4 […]
High Current Adjustable Regulator Circuit with 30V 3A Output
In this article IC LM723 chip controls the voltage. It give stable DC output, voltage and current adjustable. Output voltage range is 2V to 37V and up to 150mA and input is max 40V. High Current Adjustable Regulator Circuit with 30V 3A Output is good for lab supply and projects. With extra pass transistor it […]