30 Watt Audio Power Amplifier Schematic

By |July 2nd, 2014|

Including Preamp, Tone Controls, Reg dc Power Supply, 18 Watt into 8 Ohm – 30W into 4 Ohm loads

This project was a sort of challenge: designing an audio amplifier capable of delivering a decent output power with a minimum parts count, without sacrificing quality. The Power Amplifier section employs only three transistors and a […]

2Watt Audio Amplifier

By |July 2nd, 2014|

Designed for self-powered 8, 4 & 2 Ohm loudspeakers, Bass-boost switch

This amplifier was designed to be self-contained in a small loudspeaker box. It can be feed by Walkman, Mini-Disc, iPod and CD players, computers and similar devices fitted with line or headphone output. Of course, in most cases you will have to make two […]

Simple Darkness Activated Alarm

By |July 2nd, 2014|

Most darkness activated alarms employ opamps and some logic ICs. Here, a less expensive approach is shown based on the eternal 555, this time in monostable multivibrator mode. Components R2 and C1 represent a one-second network. When the LDR (light dependent resistor) is in the dark, its resistance is high, pulling pin 2 of […]

Speed Alarm For Cars

By |July 2nd, 2014|

In normal suburban driving you pass through so many different speed zones that it can be a nuisance having to switch speed settings. The speed display can also be a distraction. This circuit eliminates the display and the need for speed selection. Each time you exceed a […]

Portable 9v Headphone Amplifier

By |July 2nd, 2014|

High Quality One-IC unit, Low current consumptionAfter several requests by correspondents, the decision of designing a 9V powered Headphone Amplifier was finally taken. The main requirement was to power the circuit by means of a common, PP3 (transistor radio) alkaline battery. So, implementing a low current drawing circuit was […]

Gated Alarm

By |July 2nd, 2014|

Sometimes the need arises for a simple, gated, pulsed alarm. The circuit shown here employs just four components and a piezo sounder and is unlikely to be out-done for simplicity. While it does not offer the most powerful output, it is likely to be adequate for many applications. A dual […]

Model Railway Short-Circuit Beeper

By |July 2nd, 2014|

Short circuits in the tracks, points or wiring are almost inevitable when building or operating a model railway. Although transformers for model systems must be protected against short circuits by built-in bimetallic switches, the response time of such switches is so long that is not possible to immediately localise a […]

Speach Amplifier

By |July 2nd, 2014|

Suitable for teachers, lecturers, tourists’ guides etc.This circuit is intended to be placed in the same box containing the loudspeaker, forming a compact microphone amplifier primarily intended for speech reinforcement. A device of this kind is particularly suited to teachers, lecturers, tourists’ guides, hostesses and anyone speaking in crowded, […]

High Power Headphone Amplifier Using BD139-40

By |July 2nd, 2014|

Firstly, I’d like to stress that the intended use of this circuit is only one of many possible applications. Apart from the obvious usage as a headphone amplifier, the circuit can be used for a range of applications where a wide bandwidth low power amplifier is needed. Some of the […]

Super Simple 3 Watt Audio Power Amplifier

By |July 2nd, 2014|

Here is the circuit diagram of superb mini audio power amplifier, That can be power with 4.5 volt dc to 18 volts dc (maximum). This amplifier is based on TDA1015, Product of NXP Semiconductors formerly PHILIPS Semiconductors. The TDA1015 is a monolithic integrated audio amplifier circuit in a 9-lead single in-line (SIL) plastic package. […]