Electronic Circuits

Amplifier Circuits, Audio Circuits

40W amplifier using TDA1514

Description. Many electronic circuits dealing with audio amplifier circuits have been published here. This is just another one and here we use the TDA 1514 high performance hi-fi amplifier from Philips. The IC has a bunch of useful features like thermal protection, mute-standby facility, low harmonic distortion etc. The amplifier operates from a dual +25/-25 […]

555 Timer IC

Voltage doubler circuit using NE555

Description. The circuit diagram of a very simple voltage doubler using NE555 timer is shown here. Here IC NE555 is wired as an astable mutivibrator operating at around 9KHz. The base of the two transistors (Q1 and Q2) is shorted and output of the astable multivibrator (pin 3) is connected to it. When the output

Audio Circuits

3 way active cross- over network

Description. Here is the schematic of a 3 way active cross- over network circuit that finds a lot of application in audio amplifier systems. The heart of this circuit is National Semiconductor’s IC LF353 which is a dual JFET input operational amplifier with internally compensated input offset voltage. The IC LF353 has high bandwidth, low

Amplifier Circuits, Audio Circuits

2 x 32 Watts stereo amplifier

Description. The circuit given here is of a 2 x 32 Watt stereo amplifier using the famous TDA2050V IC from ST Microelectronics. The TDA2050V is an integrated monolithic 32 watt class AB audio amplifier IC available in the Pentawatt package. The IC has lot of good features like low distortion, short circuit protection, thermal shut

Amplifier Circuits, Audio Circuits

4 X 15 Watt power amplifier

Description. A lot of electronic circuits in the domain of audio amplifiers are already been published here. This circuit is a little different because it is a four channel amplifier. Each channel of this amplifier can deliver an output of 15Watts into a 4 ohm speaker. The amplifier can be operated from a single 12V

Audio Circuits, Motor Related

Automatic cooler fan for amplifiers

Description. The schematic of an automatic cooler fan for audio amplifiers is given here. The circuit automatically switch ON the cooler fan whenever the temperature of the heat sink exceeds a preset level. This circuit will save a lot of energy because the cooler fan will be OFF when the amplifier is running on low

Motor Related

Low voltage DC motor speed control circuit

Description. Here is the circuit diagram of a low voltage /low power DC motor speed controller based on the IC TDA 7274 from ST Microelectronics. The IC TDA 7274 is a monolithic integrated DC motor speed controller intended for low voltage/ low power applications. Built in internal voltage reference voltage, wide input voltage range (1.8

555 Timer IC, Tone generator circuits

Police siren using NE555

Description. A lot of electronic circuits using NE555 timer IC are already published here and this is just another one.Here is the circuit diagram of a police siren based on NE55 timer IC. The circuit uses two NE555 timers ICs and each of them are wired as astable multivibrators.The circuit can be powered from anything

Switching Circuits

Hall Effect switch

Description. The circuit diagram shown here is of a Hall Effect switch. Hall Effect sensor IC DN6848 from Panasonic is the heart of the circuit. The DN6848 has a built-in Hall Effect sensor, Schmitt trigger circuit, power supply regulator and temperature compensation circuits integrated to a single chip. High sensitivity, low drift and excellent temperature

Audio Circuits

Speaker protector

Description. When the amplifier is switched on, the speaker gets popped up by a high voltage and you can hear a loud thud sound from the speaker. This stuff is very harmful to the speaker and it drastically reduces the speaker’s life. The circuit shown here connects the speaker to the power amplifier output only

Audio Circuits

Audio line driver

Description. This is the circuit diagram of a two channel audio line driver using the high performance dual opamp IC TSH22 from ST Microelectronics. The 25 MHz bandwidth, low distortion and high output current of the IC makes it possible to drive medium impedance loads at a high level of modulation. Here both of the

Electronic Keys & Locks, Security & Saftey

One transistor code lock

Description. This is of course the simplest electronic code lock circuit one can make. The circuit uses one transistor, a relay and few passive components. The simplicity does not have any influence on the performance and this circuit works really fine. The circuit is nothing but a simple transistor switch with a relay at its

Audio Circuits

Hi-Fi DX Bass circuit

Description. Here is the circuit diagram of a passive DX bass circuit that can be used with almost all audio amplifiers. This circuit is designed by Mr. Emmanuel Chipula (emmanuel@windowshoppingmalawi.com) from Malawi and was sent to us for publication.We tested this circuit in our lab and the result was fine.Full credit of this circuit goes

Battery Circuits

24V lead acid battery charger circuit

Description. This lead acid battery charger circuit is designed in response to a request from Mr.Devdas .C. His requirement was a circuit to charge two 12V/7AH lead acid batteries in series.Anyway he did not mentioned the no of cells per  each 12V battery. The no of cells/battery is also an important parameter and here I

Audio Circuits, Automotive Circuits

Car subwoofer filter

Description. Here is the circuit diagram of a simple subwoofer filter that can be operated from a 12V DC supply. Such a circuit is very useful in automobile subwoofer applications. The circuit is nothing but a low pass filter whose pass frequency can be adjusted between 60 to 160 Hz. The circuit is designed around

Battery Circuits

Automatic changeover circuit

Description. The circuit diagram shown here is of a automatic changeover switch using IC LTC4412 from Linear Technologies. This circuit can be used for the automatic switchover of a load between a battery and a wall adapter.LTC4412 controls an external P-channel MOSFET to create a near ideal diode function for power switch over and load

Power Supplies

12V boost regulator circuit.

Description. Here is the circuit diagram of a 12V boost converter using IC LM2698 from National Semiconductors. The LM2698 is a general purpose boost converter with an 18V, 1.35A. 0.2 Ohm internal switch. This results in high efficiency power conversion to outputs ranging from 2.2V to 17V DC. The input supply voltage range is 2.2V

Power Supplies

5V buck regulator using LM2678

Description. Here is the circuit diagram of a 5V buck switching regulator based on the IC LM2678 from National Semiconductors. LM2678 series of regulators are monolithic integrated circuits which provide all necessary functions required for a buck switching regulator and can drive up to 5A loads. The IC has more than 90% efficiency and has

Radio Circuits

AM receiver using ZN414

Description. This is the circuit diagram of the simplest single chip AM radio. The circuit is designed around the IC ZN414Z which is a ten transistor tuned radio frequency receiver .The IC has only three leads and is available in the TO92 package. All necessary circuits required for an AM receiver (RF amplifier, detector and

Radio Transmitters

200M FM Transmitter

Description. A very stable and simple FM transmitter circuit is given here. With a matching antenna, this transmitter can attain a range of around 200 meters. I assembled this transmitter few years and got very good results. Let us see how the circuit works. A condenser microphone (K1) is used to pick the sound to

High Voltage Circuits

High voltage generator circuit

Description. First of all let me remind you that this circuit is a very dangerous one. The output voltage of this circuit is in Kilo volts and it can seriously injure you or kill you. Try this circuit only if you have enough experience dealing with high voltages. I have no responsibility on any hazards

Lighting Circuits

24V flasher circuit

Description. The circuit shown here works from 24V DC and can flash two 24V bulbs alternatively. The circuit is nothing but an astable multivibrator operating at 1Hz and 50% duty cycle. The lamp to be flashed is connected in place of the collector resistor (Rc) of a typical design. 2N3055 transistors which are well known

Power Supplies

Positive voltage to negative voltage converter

Description. This circuit diagram shows how to obtain a negative voltage from a positive voltage supply. Another advantage of this circuit is that, the negative voltage together with the original positive supply can be used to simulate a dual supply. The circuit is based on timer IC NE555. The NE555 is wired as an astable

Integrated Circuits

Op-Amp Comparator

In this post we will be discussing about the op-amp as a comparator.We have already discussed other applications of the op-amp in rectangular wave form generator circuits like astable (or free-running) multivibrators, monostable multivibrators (or one-shot) and bistable multivibrators (or flip-flops). To get a better understanding of operational amplifiers click here:- Operational Amplifiers (Op-amp)  Op-amp Comparator A comparator

Automotive Circuits, Test & Measurement Circuits

F to V Converter

F to V Converter Circuit using LM555 Timer Description. Here is a very simple circuit diagram of a frequency to voltage (F to V) converter. Such a circuit finds numerous applications in projects like digital frequency meters, tachometers etc. The circuit is mainly based on a LM555 timer IC. The IC is wired in mono

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