Power amplifier electronic circuits-tube audio rf amplifiers

Electronic Amplifier Circuits-Power amplifier, audio amplifier designs and circuits

August 22nd, 2009

Audio Clipping Detector Circuit

About The Circuit

 

Clipping is one of the main problems that causes distortion in amplifiers. It causes the amplitude level of a waveform to drop suddenly before it reaches the limit that it was supposed to reach. Well, here is a simple circuit that will help to detect the clipping in a waveform. The clipping can be identified as an LED is kept as the alert indicator when a clipping occours.

 

This circuit will show correct accuracy if you are able to make it on a high quality PCB. The circuit is mainly based on the working of two operational amplifers (TL 082) inside IC1. They act as window comparators. All it does is to detect the input signal and find out its positive or negative peak value. Correct calibration of the circuit can be done with the POT R5, while POT R1 has to be adjusted to the level at which the LED is supposed to glow.

 

As we can see Diodes D1 and D2 are connected to the output of the operational amplifier. They are used to drive the transistor Q1 which further drives the LED to glow. A very small time delay is induced by the capacitor C5 so as to identify rapid as well as short peaks. The circuit will easily work with the help of a 9 Volt battery. The circuit is very useful and can be used on all types of power amplifiers, pre-amplifiers and mixers.

 

Circuit Schematic

 

 

 

audio-clipping-detector-circuit.JPG

August 22nd, 2009

Simple Power Megaphone Circuit

About The Circuit

 

Here isthe circuit diagram of a simple power megaphone circuit. All you have to look out for is whether you get the perfect power and speaker matching. For that the transistors Q1 and Q2 (HEP 230) are connected in parallel. An input voltage supply of 12 Volts is required. It can be either given from a battery supply or a DC power supply. A carbon type michrophone is more than enough for the circuit to work. It is the same component that is used in our ordinary telephone sets. A Push-to-talk (PTT) switch can be easily setup if we use an ordinary carbon type michrophone.

Any type of power transisitors can be used for this circuit. You have to only look out that the transistors used are kept on heat sinks. The volume control can be adjusted wiith the help of the POT R1, through which you will get max. volume with min. distortion. Take a look at the circuit diagram given below.

 

Circuit Description

 

simple-power-megaphone-circuit.JPG

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