This document describes a battery charging circuit that uses an operational amplifier (OP-AMP) and transistor for current limiting. It includes the circuit diagram, outlines the working, and lists some resources for more information. The circuit uses a potentiometer and OP-AMP as a constant current source, with a transistor to boost the output current. A sense resistor is used to measure the charging current by dividing the voltage drop across it. The circuit provides current limiting to protect the battery during charging.

1. BATTERY CHARGING CIRCUIT
NAME : KARTHIK.J.M
ROLL NO : 42
USN : 2BV13EC035
GUIDED BY
SNEHA.V.METI

2. Presentation Outline
Introduction
Basic circuit diagram
Application
Working
Source

3. INTRODUCTION
 OP AMP is a dc coupled high gain electronic voltage amplifier with a
differential input and usually a single ended output.
 OP AMP was invented by KARL.D.SWARTZEL JR in 1941.
 OP AMP has revolutioned the analog electronic field with
its wide variety applications .
 First it was used in analog computers for arithmatic and logic
operations.

4. INTERNAL CIRCUIT DIAGRAM OF OP AMP

5. SYMBOLIC REPRESENTATION
 V+ : Non inverting input
 v- : Inverting input
 vout : Output terminal
 V+ : Non inverting input
 v+ : Positive power supply
 v- : Negative power supply

6.  Current Limiting is the practice in electronic circuits of
imposing an upper limit on the current that may be delivered
to a load with the purpose of protecting the circuit generating
or transmitting the current from harmful effects due to
a short-circuit or similar problem in the load.
 The simplest form of current limiting for mains is
fuse. A circuit breaker is another device for mains current
limiting.
LIMITING CIRCUITS

7. CONTINUED..
 Classic 2 NPN transistor current limiter
 NPN + op amp current limiter
 Mosfet current limiter

8. CHARGER WITH LIMITING CIRCUIT
 The charger circuit is fundamental unit to any battery which
makes use of limiting circuits.
 So, an charging circuit has been designed using a op amp and
hence an application of op amp is developed.
 It basically consists of an LM741 op amp
and a transistor along with resistors and to reduce the input
voltage to required value.

9. Circuit Design

10. WORKING
 This circuit uses a potentiometer and an op-amp to make a 0
- 160 mA adjustable constant current source. A transistor is
used to boost the output current of the op-amp.
 The current flowing through the transistor is limited only by
the control signal from the op-amp.
 R5 is not a current limiting resistor. R5 is a sense resistor.
 R5 is far too small and lets far too much current through
before it starts to limit current.
 Divide the voltage drop across R5 to get charging current.
 1 ohm or 10 ohms or 100 ohms for the value of R5. This
makes for very easy calculation.

11. Resources……
For more information
visit www.google.co.in
visit www.engineeringgarage.com

12. THANK YOU