Electronics

Pocket size FM receiver

Posted on

Below is the circuit idea for pocket size FM receiver using RF transistors. The circuit works off a small 4.5 volt battery or 5v USB. The heart of the circuit is the two RF transistors T1 and T2 to detect the Frequency Modulated signals.Coil L1 and the trimmer capacitor form the tuned circuit to tune […]

Electronics

Time delay relay circuit

Posted on

What is a time delay relay circuit? In a time delay relay circuit, relay contacts are closed or open after the preset time interval. Whereas in a normal relay contacts are open/closed immediately when coil is energized. It prevents the damaging effect of voltage spikes or input surge current by delaying the relay on/off. Schematic […]

Electronics

1 Watt audio amplifier for Mobile device

Posted on

About LM4890 1 Watt audio amplifier for mobile device has been designed using LM4890 power amplifier. LM4890 is primarily designed for mobile phones and other portable devices. It is capable of delivering 1 watt of continuous average power to an 8 ohm load from 5v power supply. It has a distortion of less than 1%. […]

Electronics

Plus/minus supply using LMC7660

Posted on

LM 7660 is a CMOS voltage convertor capable of converting a positive voltage in the range of +1.5 v – 10 v to the corresponding negative voltage of -1.5v to -10v using very few external components. Below is the schematic diagram for the same. We can use this get +/-5v from different sources like from […]

Electronics

Bicycle USB Charger

Posted on

This circuit has been developed to add a USB charging port to a bicycle for charging a mobile phone. The input supply for the circuit is produced by a dynamo (6V, 3W dynamo) in the bicycle. The circuit is based on LM2596-5.0. It is a 3A step down voltage regulator. LM 2596 are available in […]

Electronics

Adjustable Buck regulator with Low Ripple voltage

Posted on

The LM2576-Adjustable Buck regulator using LM2576- Adj series are monolithic IC that provides all active functions for a step-down(buck) switching regulator. The output voltage is adjustable from 1.23 v to 37 v and are capable of driving 3 am. Load with excellent line and load regulation It requires minimum number of external components. Below are […]

Electronics

Solar mobile charger circuit

Posted on

Solar mobile charger circuit using LM7805 fig1 C1 and C2 – 4700 µf This circuit is self explanatory. It uses solar panel to convert light energy to electrical energy to charge your mobile. It uses 5v regulator IC 7805 to provide constant current of 5v. Resistor R2 limits charging current to safer level. Note: if […]

Electronics

Solar power supply circuit

Posted on

This solar power supply circuit project uses the 1.2v rechargeable battery and solar panel. The solar panel charges the battery when sunlight is bright enough to produce a voltage above 1.9v. The regulator transistor is designed to limit the output voltage to 5v. courtesy- talkingelectronics.com( This solar power circuit is taken from talkingelectronics.com