Ignition Coil Buzz Box

Welcome back to Free circuit dot com.Today ,We would like to show you about automotive circuit.

This picture is a circuit for a buzz coil using a standard car battery to create. Dual timer IC 556 is used to set the frequency and the duty cycle of the coil current to be determined. One of the timer is used as an oscillator for generating the rectangular waveform 200 Hz to control (IRF740 MOSFET), while the second timer is stopped and the oscillator switching points are opened and closed (closed = a). The result is a steady stream of sparks of the ignition coil a distance of about 5 milliseconds, while the switching points are closed. Operation: Pin 8 and 12 the trigger inputs, and a timer which are driven by the points and an inverted signal of the clock output (pin 9) to produce. When the pin 9 is grounded points high, and vice versa. The signal on pin 9 controls the reset line (pin 4) of the second timer and keeps the output at pin 5 is low, while pin 4 and pin 8 is low and 12 high (still open). The 15K and 47K resistors and capacitors are 0.33uF synchronization components that the frequency and duty cycle of the second clock, which is about 4 milliseconds to 2 milliseconds apart to secure positive and negative. During the time interval is positive, the doors are always high MOSFET causing the coil to the current height of about 4 amps. This equates to approximately 80 milli joules of energy in the coil is released in the spark plug when the clock output (pin 5) moves on the ground, turn off the MOSFET. A zener diode 12 volts is placed on the node 10 and 27 ohms for the MOSFET gate input is above or below 12 volts -0.7 volts. A Zener diode 200 volts / 5 W used for the drain voltage of the MOSFET 200 and limit the useful life of the spark to expand. The circuit must operate reliably with a jumper, but the circuit operation with no load applied (the son of candle down, etc.) may cause a malfunction, because most of the energy absorbed by the Zener. You can also use a transient voltage suppressor (TVS) as 1.5KE300A 1.5KE200A or instead of the zener. This is probably a good hand, but difficult to obtain

Component List
IC1    7404   1
IC2    7490A   1
R     1 K    2
R     3.3 K    1
C  Trimmer  39 pF   1
C  Electrolyte  4.7 uF 16V   1
C  Mirra 47 nF 16 V   1
C  Mirra 10 nF 16 V   1
C  Ceramic 68 pF 50 V   1

Volt Stabilizer

Car Voltage Stabilizer Assembly

O2 meter for car circuit

Welcome back to Free circuit dot com ,Today i would like to show you in about circuit for car .

So,All really knows how to customize the level of production with an LM3914 LED?

What I’m trying to do is read a signal from a pressure sensor in my car exploded and show a more or less accurate reading of impulse (psi) with 10 LEDs. Here is the map of psi Volt:

Electronic Part

-20 = 3.4 V
-10 = 3.1 V
0 = 2.9 V
5 = 2.7 V
10 = 2.4 V
15 = 1.8 V
20 = 1.4 V

Assembly Picture

So, more or less show you need the LM3914 to ~ 1.5 volts – 3 volts to the LED. I know it has something to do with the use of resistance in some of the pins, but I can not understand. Any help is welcome! Thank you.

The O2 sensor. As a D15 B12 Nissan or Honda engines. Must be the only O2 sensor wire. No cable 3 or 4, as these O2 sensors require heating.

Solid State Relays Circuit

Welcome to Free circuit dot com ,today we have classic circuit to implement solid state relay in your electronic project .

Solid state relays are almost everywhere these days, but they are very expensive. So, your efforts to build their own salary. Especially since it’s only a few parts and circuit simple and straightforward. Solid state relay is not really at all relays. There are no “relay” is available only with electronics, connection works. It works well as a relay, you can use low voltage higher and better. “Relay” between 115/220V AC wires in place, although it was customary, the neutral conductor and leave unchanged phases and neutral.

As long as no voltage (left in picture), the phototransistor TIL111 blocks of energy, and thus is not available. To ensure that the base TIL111 is fed to the transmitter (s) through the 1M resistor. This method prevents the base of transistor BC547B will be low and remains biased ‘on’. Collector is low and the gate (g) TIC106M thyristor, which is still in the country, “off”. 4-diode bridge rectifier circuit has no power apart from a small base and collector current BC547B, which is not enough to turn over the 330-ohm resistor TIC226M triac. Current “Load”, is very small.

With an input voltage, say 5 volts, the diode in the TIL111 lights up and activates the phototransistor. The voltage drop 1MEG ohm resistor in series with 22K resistance increases demand, which block the BC547B transistor. Collector current of the fact that the AC voltage falls below a certain value, which is VA. This ensures a sufficiently large voltage drop across the resistor 330 ohms triac switches ‘on’. The voltage on triac is currently only a few volts, so that practically the whole 115/220 AC voltage on the “Upload”.

The triac is a 100nF capacitor and impedance of 47 ohms, 100nF capacitor for the 330 ohm resistor is to protect the triac to be undesirable distortions caused by small peaks. To create the possibility of this circuit with different voltages to be switched, added BF256A FET. The FET acts as a current source from the source (s) with a gate (g). This means that this FET determines the current TIL111, regardless of the input voltage (up to a certain tolerance, of course). 1N4148 diode is to protect the circuit from reverse polarity.
(Tony: TIL111 is a so-called “optical coupling” with NPN output and can be replaced with NTE3042)

Good point line, as is the separation of AC and DC voltage, so this circuit is used in many applications, about 1.5 kW, when the triac is mounted on the large size of the cooling fins.
“M” appears Triac means it’s 600volt type, “D” for 400V. So be sure to go to the M-type.

NTE replacement for this circuit are 600volt types which are more than sufficient for our 110/115VAC. Even if you decide to print for this circuit is enough space between the lines AC and non AC these tracks to be close.

DVD to RF modulator circuit

Welcome back to Free Circuits dot com,It is long time to see you as i’m busy in my working ,OK first of all,
This circuit today is a RF modulator which can be used for moduling of video signals .
P1 control the Light and P2 control the contrast of video signal.
RF modulated output signal can be received on VHF band ( about 189 MHz ).

Power Amp-TDA 7294

Welcome back to Free Circuit dot com again,Today ,I would like to present a small audio amplifier circuit with TDA7294.

You can follow by PCB thus as my post.

The described circuit uses two TDA7294 for use in stereo (2 x 80 watts) and bridge mode (1x 180 watts), configure this setting only four drivers.

To facilitate the installation of each fuel. The performance is a kind of symmetry with a simple bridge rectifier 6A, and two large electrolytic capacitors, which 10000μF 22000μF/50v. This power supply for two modules. The processor is recommended 22-0-22 to 28-0-28 / 5 A, depending on the quality of the transformer is at least 6 amps is recommended.

Parts Layout PCB

Amp TDA7294 PCB

The TDA7294 is a monolithic integrated circuit in MULTIWATT15 package for use as audio class AB amplifier in Hi-Fi field applications (stereo, powered speakers, car, high-end TV) is provided. Many thanks to the wide range of voltage and current capacity he is able to offer the highest property taxes in both 4Ω and 8Ω, to offer even in the presence of poor supply regulation, with the rejection of high-voltage power supply. The built-in mute with delay sounds easier to avoid the remote mode off.

preamp power supply

This is IRRESPONSIBLE and DANGEROUS!!

Welcome back to Free circuit dot com again,today i would like to present the preamp power supply circuit.

this circuit is small and easy to assembly,we will use IC regulator 7915 and 7815 for main control voltage.

About all capacitors are filter noise and frequency.

We will take diodes to allow an electric current to pass in one direction (called the diode’s forward direction), while blocking current in the opposite direction

DC to DC Converter with 450Watt

For developper who would like to power supply for your amplifier or other load.Circuit today will be show you in DC to DC converter circuit with 450 Watts.

+/- 50 Vdc for Output Voltage , Voltage adjustable between 47-55 Vdc.

No problem in output Voltage drop when connect load.

We have verified the circuit already. For more detail ,Could you look at the picture thus as below.

DC to DC 50V 450W Circuit

Mosfet Amplifier K1058 circuit

Welcome back to Free circuit dot com,We would like to present audio amplifier circuit as this amplifier consists of two completely separate mono amp for each channel has its own power supply, so zero inter-channel crosstalk, a common phenomenon in amplifiers, the same diet. 0 – - 40VAC at 640VA To the full power any 40VAC transformer should be evaluated to obtain. Unlike many designs, referring to the capacitors to supply the current peaks, I prefer the raw power available from the transformer, have resulting in faster transients.

Mosfet 200W Class A PCB

Although RAS-300 specifications moderate, if they immediately hear the huge reserves of power available and not cause of fear that something, this would give a very loud while driving amplifiers. You hear nothing but the truth without distortion at any level, and I guarantee you that this amp the best qualities of the connected devices reveal.

Mosfet 200W Class A Parts Assembly