Showing posts with label small. Show all posts
Showing posts with label small. Show all posts
Sunday, September 7, 2014
Small transistor amplifier Ideals
Currently, ICs has been used in many audio amplifiers,especially small circuit. It is convenient to use transistors.But when you need to use transistors, it has several advantages, such as saving you can take old equipment come to made small circuits easier than the IC. Which may be difficult to find. Take a look at these circuits. Maybe you get the idea of it.
Low impedance mini amplifier
This circuit can apply to signal sound source that has low impedance , such as from 4-16 ohm size loudspeakers or telephone earphone that use to replace , Micro phone. If use a loudspeaker replaces the rapidity will enough in sound checking that has been born from walking. The output this can feed reach input of high power amplifier the other next.
Power Amplifier OTL by AC176+AC126
Mr Somsak is my friend who like to make power amplifier so much. but he do not well electronic man. I so introduce he need make easy project before. This circuit is simple power amplifier OTL that mini watt output but is older circuit.
They uses transistors example number are AC176 , AC126 and BC109. which there has other a few components. They are used power Supply Voltage 9Volt only. I hope it will be once circuit so you like and well ideas.
Power Amplifier OTL Cassette Radio Booster by TIP41+TIP42
This is mini Power Amplifier OTL for Cassette Radio Booster. it have transistor TIP41 + circuits of TIP42 Drive speaker sound. Volt supply see in image.
Simple Amplifier by Transistor AC128
I find this in my old circuit electronics book. It is very a small power amplifier, but good quality audio class AB amplifier in hi-fi applications. The component capable of delivering 2W continuously an used the AC128 thansistor into a 8 ohm load and 5W peak. with the proper 9 volt unregulated power supply.
This circuit can apply to signal sound source that has low impedance , such as from 4-16 ohm size loudspeakers or telephone earphone that use to replace , Micro phone. If use a loudspeaker replaces the rapidity will enough in sound checking that has been born from walking. The output this can feed reach input of high power amplifier the other next.
Power Amplifier OTL by AC176+AC126
Mr Somsak is my friend who like to make power amplifier so much. but he do not well electronic man. I so introduce he need make easy project before. This circuit is simple power amplifier OTL that mini watt output but is older circuit.
They uses transistors example number are AC176 , AC126 and BC109. which there has other a few components. They are used power Supply Voltage 9Volt only. I hope it will be once circuit so you like and well ideas.
Power Amplifier OTL Cassette Radio Booster by TIP41+TIP42
This is mini Power Amplifier OTL for Cassette Radio Booster. it have transistor TIP41 + circuits of TIP42 Drive speaker sound. Volt supply see in image.
Simple Amplifier by Transistor AC128
I find this in my old circuit electronics book. It is very a small power amplifier, but good quality audio class AB amplifier in hi-fi applications. The component capable of delivering 2W continuously an used the AC128 thansistor into a 8 ohm load and 5W peak. with the proper 9 volt unregulated power supply.
Original article sourse eleccircuit.com.
Friday, August 22, 2014
Simple 4 Transistor Amplifier for Small Speakers
The schema above shows a 4-transistor utility amplifier suitable for a variety of projects including receivers, intercoms, microphones, telephone pick-up coils, and general audio monitoring. The amplifier has a power isolation schema and bandwidth limiting to reduce oscillations and "motorboating". The values are not particularly critical and modest deviations from the indicated values will not significantly degrade the performance.
Three cell battery packs giving about 4.5 volts are recommended for most transformerless audio amplifiers driving small 8 ohm speakers. The battery life will be considerably longer than a 9 volt rectangular battery and the cell resistance will remain lower over the life of the battery resulting in less distortion and stability problems.
Three cell battery packs giving about 4.5 volts are recommended for most transformerless audio amplifiers driving small 8 ohm speakers. The battery life will be considerably longer than a 9 volt rectangular battery and the cell resistance will remain lower over the life of the battery resulting in less distortion and stability problems.
4 Transistor Amplifier for Small Speakers Circuit Diagram
The amplifier may be modified to work with a 9 volt battery if desired by moving the output transistors bias point. Lowering the 33k resistor connected from the second transistors base to ground to about 10k will move the voltage on the output electrolytic capacitor to about 1/2 the supply voltage.
This bias change gives more signal swing before clipping occurs and this change is not necessary if the volume is adequate. As before, the two 4.7 ohm resistors may be replaced with a single 10 ohm resistor in series with either emitter.
This bias change gives more signal swing before clipping occurs and this change is not necessary if the volume is adequate. As before, the two 4.7 ohm resistors may be replaced with a single 10 ohm resistor in series with either emitter.
Saturday, August 16, 2014
Brightness Control for small Lamps
This device was designed on request, to control the light intensity of four filament lamps (i.e. a ring illuminator) for close-up pictures with a digital camera, powered by two AA or AAA batteries. Obviously it can be used in other ways, at anyones will.
IC1 generates a 150Hz squarewave having a variable duty-cycle. When the cursor of P1 is fully rotated towards D1, the output positive pulses appearing at pin 3 of IC1 are very narrow. Lamp LP1, driven by Q1, is off as the voltage across its leads is too low. When the cursor of P1 is rotated towards R2, the output pulses increase in width, reaching their maximum amplitude when the potentiometer is rotated fully clockwise. In this way the lamp reaches its full brightness.
LP1 could be one or more 1.5V bulbs wired in parallel. Maximum total output current allowed is about 1A.
R2 limits the output voltage, measured across LP1 leads, to 1.5V. Its actual value is dependent on the total current drawn by the bulb(s) and should be set at full load in order to obtain about 1.5V across the bulb(s) leads when P1 is rotated fully clockwise.
Parts:
P1 470K Linear Potentiometer
R1 10K 1/4W Resistor
R2 47K 1/4W Resistor (See Notes)
R3 1K5 1/4W Resistor
C1 22nF 63V Polyester Capacitor
C2 100µF 25V Electrolytic Capacitor
D1,D2 1N4148 75V 150mA Diodes
IC1 7555 or TS555CN CMos Timer IC
Q1 BD681 100V 4A NPN Darlington Transistor
LP1 1.5V 200mA Bulb (See Notes)
SW1 SPST Switch
B1 3V (Two 1.5V AA or AAA cells in series, etc.)
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