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Simple pre-amplifier with transistors BC547

The preamplifier circuit is a circuit that extends the signal from the source sound to signal the strength to go into a power amplifier circuit to trigger the required sector preamplifier is also due to signal from the source voice Some levels. sounds very light, such as tape or tuner, some will have strength of signals in the heart uV is required to use the preamplifier circuit expanded signal strength to strength in the area mV to access the power amplifier for amplifier efficiency.

By entering into power supply 9volt circuit Q1 and Q2 to a direct coupling circuit to transmit better. When the signal input through the C1 coupling into the signal to Q1.
Amplifier to a level of C to stand out in Q2 into the amplifier once again to provide better stability. Then signal to leave the output pin C of Q2 through C6 coupling signal from output and the output signal a part of Q2 will feed black feedback through to the C4, C3 and R3 comes to the pin E in Q1 in order to help the range of frequency response.
With superior audio output that can be connected to the amplifier region.

Be the first to comment - What do you think? Posted by admin - June 8, 2010 at 9:57 pm

Categories: Pre Amplifier Tags: BC547, simple preamplifier circuit, Transistor preamplifier

Easy Test power battery by BC547

A friends at use the battery often meet a problem electric its energy is finished in important always may many good if there is the circuit warns before or there is the way checks at the beginning. By this circuit use the transistor just one and don’t have to have power supply source. By this circuit designs to come to use battery 3V – 15V. By fining decorates with VR1. When level voltage agree more location dot keeps LED1 as a result bright immediately. This circuit uses electronic part the a little , then easy in building , request friends , enjoy please yes.

Be the first to comment - What do you think? Posted by admin - October 11, 2008 at 7:40 am

Categories: Battery, Detector, Meter Tags: battery tester, BC547, led display

ECM Mic Preamplifier by BC549

A microphone amplifier that may be used with either Electret Condenser Microphone (ECM) inserts or dynamic inserts, made with discrete components.
Both transistors should be low noise types. In the original circuit, I used BC650C which is an ultra low noise device. These transistors are now hard to find but BC549C or BC109C are a good replacement. The circuit is self biasing and will set its quiescent point at roughly half the supply voltage at the emitter of the last transistor.

Read More Source:Andy Collinson http://www.mitedu.freeserve.co.uk/Circuits/Audio/ecmmic.html