Free Electronic Circuit Schematics » BC547

Micro Phone Amplifier circuit with BC549,BC547

admin — Mon, 01 Aug 2011 19:12:01 +0000

Microphone preamp circuit

Welcome back to free circuit dot com ,today we have amplifier for microphone with transistor number BC549,BC547 for drive signal.

As this is a simple microphone preamplifier circuit between microphone and stereo amplifier can be used.
The circuit amplifier microphone suitable for use with a normal stereo amplifier line / CD / aux / tape inputs.

The microphone preamplifier can be both dynamic and electret microphone inputs (preamplifier provides foe electret microphone elements). The idea of this circuit is provided that the design as easy as possible for easy build.
Which was my goal when I make a simple external microphone preamplifier for my mixer needed. The behavior of the circuit is nothing better, but with many not so serious projects are used.

6V to 12V Converter Circuit with BC547-BD679

admin — Mon, 18 Jan 2010 16:10:52 +0000

This inverter circuit can to 800mA of 12V power supply with a 6V. For example could you 12V Car Accessories (UK turning into a 6V?) Car. The circuit is simple, more than 75% efficiency and very helpful. By changing a few components you, you also change for different voltages.

6V to 12V Converter Circuit

Electronic Part List

R1, R4 2 .2 K 1/4W Resistor
R2, R3 47K 1/4W Resistor
R5 1K 1/4W Resistor
R6 15K 1/4W Resistor
R7 33K 1/4W Resistor
R8 10K 1/4W Resistor
C1, C2 0.1uF Ceramic Disc Capacitor
C3 470uF 25V electrolytic capacitor
1N914 diode D1
D2 Diode 1N4004
D3 12V 400mW Zener Diode
Q1, Q2, Q4 BC547 NPN transistor
BD679 NPN transistor Q3
L1 See Notes
Notes
1. L1 is a custom inductor wound with about 80 turns 0.5 mm magnet wire a ring around the core with an outer diameter of 40 mm.

2. Different values of D3 can be used to obtain different output voltages from 0.6V to 30V is about. Note that at higher voltages, the circuit could perform just as well and can not produce much electricity. You may need to use a larger C3 for higher voltages and / or higher currents.

3. You can use a larger value for C3, in order to achieve a better filtering.

4. The circuit requires about 2A from the 6V supply to provide the full 800mA at 12V.

Motorcycle Alarm Circuit and PCB for Prevent steal.

admin — Tue, 16 Jun 2009 13:23:21 +0000

This project is prevented steal circuit which be kit to be easy the system is simple. but We thinks the project should be help to protect your motorcycle or accessories. This principle is simple be the system Close Wire Loop.

: motorcycle alram circuit

The circuit is going to make a noise to warn that circuit turn , with the circuit used power electric energy while standby very low 0.5 uAmp. When relay working as a result use current about 70mAmp . The usability can use in an automobile,house door, leak round a house or the other. That time an electric line turn system , Relay command sent beep danger circuit work immediately.