LM7555 | Electronic Project Circuits

Posts Tagged ‘LM7555’

Tone Burst Generator by LM555

Friends take an interest try build Tone Burst Generator be simple is. Try this circuit like sure because use IC 7555 , highly popular again. Assure that not sure difficult press the the secretariat of the senate S1 a loudspeaker will utter to come out immediately. When liberate S1 already the sound may loud again next many second. The C2 and R4 control time drag. The C1 control the frequency.( Use the integrated circuit IC 7555 use power source a little more IC 555 very )The detail is other see in the circuit request have fun Tone Burst Generator please sir.

Be the first to comment - What do you think? Posted by admin - August 12, 2008 at 11:13 am

Categories: Alarm systems, Audio diagram Tags: LM555 audio generator, LM7555, Tone Generator

Sequential Brake/Turn Lights with IC 4094,7555

Bar-mode LED-cluster sequencer Can drive up to 16 clusters

This circuit, designed on request, allows up to 16 LED clusters illuminate in bar-mode sequence. LED sequencing will start when the Brake pedal is pressed (or Turn Lights are switched-on) and, when the last cluster illuminates, all LED clusters will remain steady on until the Brake pedal is released or Turn Lights are switched-off.

Sequential Brake/Turn Lights with IC 4094,7555

Parts:
R1,R5____________1K 1/4W Resistors
R2______________33K 1/4W Resistor
R3_____________100K 1/2W Trimmer Cermet
R4_______________1M 1/4W Resistor
R6,R7,R8________10K 1/4W Resistors
R9_______________4K7 1/4W Resistor
R10_____________33R 1/4W Resistor (See Notes)
[...]
D1______________LED (Any dimension, shape or color)
D2,D3________1N4002 100V 1A Diodes
D4–D15________LEDs High brightness, high efficiency red types (See Notes)
Q1___________2N3819 General-purpose N-Channel FET
Q2____________BC337 45V 800mA NPN Transistor
Q3____________BC547 45V 100mA NPN Transistor
IC1____________7555 or TS555CN CMos Timer IC
IC2,IC3________4094 8-stage shift-and-store bus register IC
SW1____________SPST Brake/Turn Lights Switch

Please read more at the original source :http://www.redcircuits.com//Page105.htm
Thank you.

Be the first to comment - What do you think? Posted by admin - September 10, 2007 at 10:32 pm

Categories: Automotive, LED Flasher, Lighting Tags: Automotive, lamp flasher, led display, LM7555

High-voltage circuits by 7555

This is a pulse-mode transformer circuit that I have some experience with.
I used this successfully in combination with a Polaroid transducer.

Introduction
The circuit can be used to generate a voltage of about 70V using a current of about 4 mA @ 6V input voltage. The use of an easily available stroboscope trigger coil makes it quite small.
How it works
The integrated circuit is a 7555 generating a 50/50 square wave of around 100 kHz. The square wave’s rising edges momentarily trigger the transistor into conduction, causing current to flow through the primary of the stroboscope transformer. The current pulse in the primary causes a much larger voltage pulse in the secondary of the transformer, thereby charging the output capacitor through the diodes.

Components
I’m using the 7555 (CMOS variety of the NE555) to generate the square wave, because it behaves much better with respect to power supply transients than the NE555. The circuit topology used here makes it possible to generate a 50% duty cycle square wave with only few external components (the resistors from output to treshold/trigger and the capacitor between treshold/trigger and ground).

The type of transistor is not very important I think. I just used a BC550 because I had it available. On the rising edge of the square wave, the transistor is switched on through the capacitor. It is quickly switched off, because the capacitor discharges through the resistor between base and ground. I connected a diode across the transistor’s emitter and collector, to protect it against the negative voltage spike from the primary winding.

The stroboscope trigger coil is a 4 kV type, meaning that it is supposed to convert a 300V pulse to 4 kV in its original application (a step-up ratio of about 13). There are also 6 kV types available, perhaps they give better results. The primary and secondary windings share a common connection, hence there are only 3 wires instead of 4. The 100 ohm resistor in series with the coil limits the continuous current, while the capacitor connected to the coil makes sure that the instantaneous current through the coil is not limited.

The diodes I’m using are ordinary 1N4148 diodes (equivalent to 1N914). They have a breakdown voltage (reverse conduction voltage) of about 75V, so I used two in series, just to be sure.

The output capacitor is quite small at 100 nF. I haven’t tried touching it yet when the circuit was operating, please beware of the high voltage. Shorting the capacitor give a nice little spark.
To connect the bias to the microphone, a resistor of several mega-ohms is used. The high resistance is no problem because the microphone doesn’t draw any continuous current.

Read more Source:http://bertrik.sikken.nl/bat/hv.htm