Loublet Schematic

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Wednesday, November 12, 2014

Long Interval Pulse Generator

A rectangular-wave pulse generator with an extremely long period can be built using only two components: a National Semiconductor LM3710 supervisor IC and a 100-nF capacitor to eliminate noise spikes. This circuit utilises the watchdog and reset timers in the LM3710. The watchdog timer is reset when an edge appears on the WDI input (pin 4). If WDI is continuously held at ground level, there are not any edges and the watchdog times out. After an interval TB, it triggers a reset pulse with a duration TA and is reloaded with its initial value. The cycle then starts all over again. As a result, pulses with a period of TA + TB are present at the RESET output (pin 10).

Circuit diagram:

Long-Interval Pulse Generator Circuit Diagram

As can be seen from the table, periods ranging up to around 30 seconds can be achieved in this manner. The two intervals TA and TB are determined by internal timers in the IC, which is available in various versions with four different ranges for each timer. To obtain the desired period, you must order the appropriate version of the LM3710. The type designation is decoded in the accompanying table.

The reset threshold voltage is irrelevant for this particular application of the LM3710. The versions shown in bold face were available at the time of printing. Current information can be found on the manufacturer’s home page (www.national.com). The numbers in brackets indicate the minimum and maximum values of intervals TA and TB for which the LM3710 is tested. The circuit operates with a supply voltage in the range of 3–5 V.

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Wednesday, October 29, 2014

Motor Generator Stepper

Stepper motors are a subject that keeps recurring. This little circuit changes a clock signal (from a square wave generator) into signals with a 90-degree phase difference, which are required to drive the stepper motor windings. The price we pay for the simplicity is that the frequency is reduced by a factor of four. This isn’t really a problem, since we just have to increase the input frequency to compensate. The timing diagram clearly shows that the counter outputs of the 4017 are combined using inverting OR gates to produce two square waves with a phase difference. This creates the correct sequence for powering the windings: the first winding is negative and the second positive, both windings are negative, the first winding is positive and the second negative, and finally both windings are positive.

Circuit diagram: Stepper

Stepper Motor Generator Circuit Diagram

Internally, the 4017 has a divide-by-10 counter followed by a decoder. Output ‘0’ is active (logic one) as long as the internal counter is at zero. At the next positive edge of the clock signal the counter increments to 1 and output ‘1’ becomes active. This continues until output ‘4’ becomes a logic one. This signal is connected to the reset input, which immediately resets the counter to the ‘zero’ state. If you were to use an oscilloscope to look at this output, you would have to set it up very precisely before you would be able to see this pulse; that’s how short it is. The output of an OR gate can only supply several mA, which is obviously much too little to drive a stepper motor directly. A suitable driver circuit, which goes between the generator and stepper motor.

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Saturday, September 13, 2014

Simple Bells Ring Generator Circuit Schematic

This schema generates a dual-tone bells ringing similar to most door-bell units. It can be used in many applications other than door-bell. In the Notes below several options will be given in order to suit different needs. The schema as shown in the diagram generates a "Ding-tone" when P1 is pressed and a "Dong-tone" when P1 is released. IC1D is the first-tone frequency generator and IC1F generates the second-tone.

Q2, Q5 and related components act as shape and decay controls of the two tones, trying to imitate as close as possible the bells sound. Their outputs are mixed (R7 & R13), filtered (C5) and boosted by a simple class-A audio amplifier (Q3 & Q4) in order to drive the loudspeaker. The amplifier is switched-on by Q1 when P1 is pressed, then is switched-off some seconds after P1 is released: this time-delay is fixed by C1 & R2. In this way the schema will draw a negligible current when in stand-by mode.

Simple Bells Ring Generator Circuit diagram:

bells ring generator schematic schema diagram

Bells Ring Generator Schematic Circuit Diagram

Parts:

R1,R3,R7,R9,R13_10K 1/4W Resistors
R2_______________1M5 1/4W Resistor
R4______________27K 1/4W Resistor
R5,R11__________47K 1/4W Resistors
R6,R12_________220K 1/4W Resistors
R8_______________2M2 1/4W Resistor
R10_____________33K 1/4W Resistor
C1_______________2µ2 25V Electrolytic Capacitor
C2______________47µF 25V Electrolytic Capacitor
C3,C8___________10µF 25V Electrolytic Capacitors
C4,C7___________10nF 63V Polyester Capacitors
C5,C6__________100nF 63V Polyester Capacitors
C9_______________4µ7 25V Electrolytic Capacitor
C10______________1µF 25V Electrolytic Capacitor
D1-D5_________1N4148 75V 150mA Diodes
IC1__________MC14106 or 40106 Hex Schmitt Inverter IC
Q1_____________BC337 45V 800mA NPN Transistor
Q2,Q3,Q5_______BC238 25V 100mA NPN Transistors
Q4 ____________BC327 45V 800mA PNP Transistor
PH______________Photo resistor (any type) (see Notes)
P1______________SPST Pushbutton (see Notes)
SW1_____________SPST Switch
SPKR____________8 Ohm Loudspeaker
B1______________3V Battery (two 1.5V AA or AAA cells in series etc.)
Parts added to optional modification:
R14____________220K 1/4W Resistor
R15______________1M 1/4W Resistor

Notes:

To obtain a "Ding-Dong" operation when pushing on P1, no matter when it is released, you must modify the schema as shown in the frame placed at the low-right corner of the schema diagram. D4 must be removed. C10 & R15 set the time-delay separating first and second tone.
To obtain a one-tone-only generator, wire the schema as in the optional modification, making the following changes:
C9 = 100nF 63V Polyester Capacitor.
Omit R9 to R13 & R15; C7, C8 & C10; D2, D4, D5 & Q5.
Connect to negative supply pins 11 & 13 of IC1 and left open pins 10 & 12.
An amusing application of this schema wired as in the original schematic, is to use a photo-resistor in place of P1, then placing the unit near the flashing lamps of your Christmas tree. A soft bell sound may be heard at switch-on and switch-off of the lamp chosen.
To obtain higher output power you may substitute R8, Q3 & Q4 with an audio amplifier IC like the LM386 or LM380. In this case power supply must be raised to 6 - 12V but at the same time R4 & R10 should be changed to adjust bell-tone frequencies.
Good tone frequencies are roughly 2000 and 1650Hz respectively.
When in stand-by mode, current drawing of the schema is 200µA @ 3V supply: therefore SW1 can be omitted.

Source: Red Free Circuit Design

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Saturday, September 6, 2014

Simple Clock pulse Generator with CD4049

If you want to generate clock with CD4049 CMOS you can do as the follow picture.The typical resister values is 100K and Capacitor is 0.01-0.1uF.The output frequency is about 1/1.1RC ___Hz

Simple Clock pulse Generator with CD4049 Circuit Diagram

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Sunday, August 31, 2014

High Voltage Generator Solid State Tesla Coil

High Voltage Generator|Solid State Tesla Coil Circuit

Notes

1. T2 is a high voltage flyback transformer salvaged from an old TV, or ordered from Fair Radio Sales (see Where To Get Parts). Look for the biggest, most intimidating transformer you can find. Old tube TVs are a good place to look. The transformer should not have a rectifier built in.

2. You will need to rewind the transformers primary. First, remove the old primary, being careful not to damage the high voltage secondary. If the transformer is wound with all windings incased in plastic, use another transformer. Second, wind on 5 turns of 18 AWG wire, twist a loop (center tap), and then wind on 5 more turns. This becomes winding C-D. Now, wind on 2 turns of 22 AWG wire, twist a loop, and wind on 2 more turns. This becomes winding A-B.

3. Q1 and Q2 will run HOT if not used with a large heatsink. After the schema has been running for a minute or two, you should still be able to put your finger on the transistors without being burnt. Also, R1 and R2 will run hot.

4. If you experience arcing on the exposed transformer leads, select a lower voltage for T1. If you are powering the schema with a power supply (see Power Supply), just crank down the voltage.

5. For a real high voltage output, connect a voltage multiplier (from an old TV or computer monitor) to the output of T2.

6. If the schema does not work, reverse connections A and B.

Parts,Total Qty,Description and Substitutions here :

R1 1 27 Ohm 5W Resistor 27 Ohm 10W Resistor
R2 1 240 Ohm 5W Resistor 240 Ohm 10W Resistor
BR1 1 50 Volt, 6 Amp Bridge Rectifier
C1 1 8000uf, 35 Volt Capacitor
Q1, Q2 2 2N3055 NPN Power Transistor
T1 1 24V 5A Transformer (See "Notes")
T2 1 TV Flyback Transformer (See "Notes")
S1 1 115V 3A SPST Switch
MISC 1 Case, Wire, Heatsinks, Line Cord

Via

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