PWM Speed Rotation Forard-Reverse and Regenerative Braking

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This is PWM Speed DC motor Rotation circuit. It can Forard-Reverse and Regenerative Braking function. By this circuit use a signal PWM control the speed of DC 12V motor with Power mosfet IRF150. The relay RY1 use control Reverse with the digital alarm , change , Q10. The Relay RY2 work be , function brake resistor. By control Run or stop with the digital alarm with . The F1 , use protect through the circuit. The D1 use for protect current turn back from DC Motor. The detail is other , please see in the circuit.

LED Voltmeter for car battery by LM324

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The circuit, is a comparator, can measure with step of 1Volt, the voltage of battery of car. The clue of voltage become after comparison of voltage of battery, that is applied in the inverting inputs of amplifiers, with voltages of reference that are produced by a Zener D1,the value of which is such so that it present good thermic stability. With the RV1, we regulate the gradation of voltage that we want.


The optical clue become from four Led.
R1=1K2 R6=10K D2-3-4-5=LED
R2-3-4=680R R7-8-9-10=1K IC1=LM324
R5=15K D1=5V6 /0.5W Zener RV1=10K trimmer
Source :: http://users.otenet.gr/~athsam/voltmeter_with_led_for_car_battery.htm

LED VU Meter by IC LM3914 Meter & Testing Circuit :

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This is Circuit LM3914 LED VU Meter.
use IC LM3914 and Transistor BC109C.
For Display power Music by LED

VU meter circuit for LM3915 Meter & Testing Circuit :

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This circuit uses just one IC and a very few number of external components. It displays the audio level in terms of 10 LEDs. The input voltage can vary from 12V to 20V, but suggested voltage is 12V. The LM3915 is a monolithic integrated circuit that senses analog voltage levels and drives ten LEDs providing a logarithmic 3 dB/step analog display. LED current drive is regulated and programmable, eliminating the need for current limiting resistors. The IC contains an adjustable voltage reference and an accurate ten-step voltage divider. The high-impedance input buffer accepts signals down to ground and up to within 1.5V of the positive supply. Further, it needs no protection against inputs of ?35V. The input buffer drives 10 individual comparators referenced to the precision divider. Accuracy is typically better than 1 dB.

source : http://www.free-electronic-circuits.com

LED Bargraph Readout by IC LM339 Meter & Testing Circuit

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LED Bargraph Readout by IC LM339
This circuit simple LED Volt Meter,
LED Bargraph Readout by IC LM339
R1 Control LED/2-3mV
LED Display 4 LED.

Car Temperature Gauge by IC CA3162 + CA3161 Car- Automotive - Motocycle Circuit page 01

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The Car Temperature Gauge is basically the same circuit as
March's project with some minor changes to the input circuit.
This circuit will display the water temperature
to 1 degree resolution.


From :: http://home.maine.rr.com/randylinscott/apr99.htm

Meter & Testing Circuit Low Power LED Voltmeter by LM3914

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Meter & Testing Circuit :Low Power LED Voltmeter by LM3914


Low Power LED Voltmeter by LM3914

Introduction

This is a low power voltmeter circuit that can be used with alternative energy systems that run on 12 and 24 volt batteries. The voltmeter is an expanded scale type that indicates small voltage steps over the 10 to 16 volt range for 12 volt batteries and over the 22 to 32 volt range for 24 volt batteries. Power consumption can be as low as 14mw when operated from 12V and 160mw when operated from 24V. It is possible to set the meter to read equal steps across a variety of upper and lower voltages. The meter saves power by operating in a low duty-cycle blinking mode where the LED indicators are only on and consuming power briefly during a repeating 2 second cycle. The circuit may be switched to a high power mode where the active LED stays on at all times.

Different colored LEDs may be used for the voltage level indicators, this allows the battery state to be read in the dark. With the new blue LEDs, it is possible to have a nice looking rainbow of colors using two each of red, amber, yellow, green, and blue LEDs. The circuit will also work with inexpensive and common red LEDs. If the circuit is to be used in sunlight, ultra-bright LEDs should be used, although even those may be hard to read without some kind of sun shield.

Typical uses include the monitoring of portable battery operated systems and indoor wall mounted home power system charge indicators. The cost of the parts for the circuit is around $25.00 (US) and the parts are commonly available, except for the optional blue LEDs. If blue LEDS are used, expect to pay a premium for them, they cost several dollars each, compared to around 15 cents for the other colors. The blue LEDs do look nice in any case.

The circuit may be built with either the CMOS ICM7555 timer or the more common bipolar 555 timer. The 7555 timer will provide much more efficient operation and should be used for systems with small batteries. The volt meter works nicely with the solar charge controller and low voltage disconnect circuits described in the home-brew section of Home Power #60 and #63.

Network Controller Using GPIB

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Network  Controller Using GPIB

Overview

The eZ80F91 processor is used by the network GPIB controller for a number of critical functions to be integrated into a single device to provide a feature-rich solution that is low cost.

Details

The General Purpose Interface BUS (GPIB) is a multipoint, 8-bit parallel bus that uses a 3-wire handshake to acknowledge each byte data, which is invented by Hewlett-Packard back in the 1960’s. The reason for this creation is due to the existence of test equipment such as signal generators, power supplies, oscilloscopes, and others that are usually used in compliance, manufacturing, and other applications where they are required. The GPIB allows such equipments to be easily controlled and connected together.

The GPIB driver is the heart of the controller where a fully compliant GPIB bus controller in software is implemented using the external GPIO lines of eZ80F91. The cost and complexity of the processor are reduced with the inclusion of an embedded Ethernet MAC. A total of 15 devices are allowed by the bus with up to 2m of separation between each device and a maximum bus length of 20m. the ZTP TCP/IP protocol stack is used to build the software in controller.

Designing a Multimeter for Power Supply Unit

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Designing a Multimeter for Power Supply Unit

Overview

The project aims to develop a multimeter that can be used to measure the output voltage and current in a PSU wherein at the negative rail, the current sense shunt resistor is connected in series with the load.

Details

The main PSU can be acquired with only a single supply voltage while being able to control an electric fan used for the main heatsink to be cooled, which is an additional feature. A One Touch Button Setup is used to adjust the power threshold at which the fan switches ON. All the functions of the multimeter are handled by a single Atmel ATmega8 microcontroller as the multimeter can be used as panel meter due to the compact construction.

The multimeter can interact well with HD44780 controller based standard LCD as the system uses a single-sided PCB. The voltage measurement resolution stands at 10mV since it can measure 10mA current measure resolution a 10mV voltage measure resolution. The LCD connector is used to deliver the programming signals and the programming cable can be made using an old PC HDD cable. The circuit must be supplied with 5V during the programming of multimeter circuit.

6 Digit USB LED Display Known as USB7

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6-Digit  USB LED Display Known as USB7

Overview

The project uses a USB virtual COM port in order to control the 6-digit LED display USB7.

Details

A reliable USB virtual serial port is being provided by the USB7 which uses a single microcontroller. For occasions where a computer monitor is not ideal, the gap between the real world display and computer software is being bridged by the 6-digit 7-segment display. This is possible by using the serial port or parallel port which no longer exists in modern computers along with different logic ICs.

The Communication Device Class (CDC) is used by the USB virtual COM port (AVR-CDC) which is a USB-RS232C interface. It can operate extremely well on low speed USB with slower speed, which makes this its biggest advantage. This signifies that in order to accelerate the 4800bps 8N1, an ATtuny45 is enough to be used. Since the ATtiny45 is so far the cheapest component for USB-232C interface type, it saves a lot of money on building this project.

The versatility in display selection is allowed by the standard 0.56” common-anode display format. The USB7 PCB is the backbone of the project while the ATmega48 functions as the brain.

Construction of LED Micro-Readerboard

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Construction of LED Micro-Readerboard

Overview

The LED Micro-Readerboard utilizes a common-cathode alphanumeric LED display that spells out simple programmed messages and one letter at a time.

Details

This open-source project is the second version of its kind which features longer battery life and a new set of phrases including optional holiday phrases. A new message is picked by the device from its memory to repeat each time the power switch is turned OFF and back ON. In case a holiday ornament is used, a bank of optional holiday messages can be enabled with 15 phrases included from the default firmware. The source code under the GPL can reprogram the LED Micro-Readerboard.

Alongside with the kit are the printed instructions, a battery box with switch, a superbright alphanumeric LED display, and a pre-programmed Atmel ATtiny2313 microcontroller. The circuit requires only two AA batteries. Also used in the kit is the ultra-high brightness LED display with deep red 16-segment alphanumeric display. Each LED segment will be ON only for very small amount of time since the display is run in a low-duty cycle mode. The display is still readably bright while drawing small enough average current because the display is so efficient.

Creating Lissajous Figures from POV

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Creating  Lissajous Figures from POV

Overview

The project uses the persistence of vision as well as two axes of motion in order to produce Lissajous figures.

Details

In systems where oscillation occurs in more than one direction, interesting curves occur which pertains to the Lissajous figures. Two axes of motion were used to make the display wherein a row of LEDs is contained in the first axis with a back and forth movement of the light. The 1-D LED display was used by the second axis to produce a pendulum on a simple bearing by rocking it back and forth. A hanging file folder frame was used to hold the pendulum up with some electrical tape to make it less slippery along with a wooden dowel. Below this wooden dowel on a couple of skinny bamboo skewers hangs down the LED display. By moving the mass, the pendulum frequency gets finely tunable.

On a small board with 12 blue LEDs, an ATmega168 AVR microcontroller was used for the LED display. To give a nice diffuse surface visible from any angle, the 12 regular blue LEDs were taken and sanded with their anodes being attached to the pins of the ATmega168.

Offset Voltage and Bias Current Compensation

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Bias Current and Offset Voltage Compensation

Up until now we have mostly considered ideal op-amps in our discussion.

We must, however, introduce some non-ideal characteristics, since they will have an effect on the op-amp operation.

Transistors within the op-amp must be biased so that they have the correct values of base and collector currents and collector-to-emitter voltages.

Ideal op-amp has no input current at its terminals.

In practice, op-amps have small input bias currents (in the nA range).

There is also a small offset voltage between the inputs.

Effect of an Input Bias Current

Consider the inverting amplifier circuit shown below.

If the input voltage is zero, there should be zero current coming into the inverting input of the op-amp.

However, there is a small bias current, I1, that goes through Rf.

This current creates a voltage at the output equal to I1Rf.

This is the error voltage.

The same voltage will be seen at the output of a noninverting amplifier.

If we look at the voltage follower circuit shown below, it is easy to see that the output error voltage is –I1Rs.

Bias current compensation in a voltage-follower

Somehow we need to compensate for the error voltage due to the bias currents.

In a voltage follower it is enough to add a resistor, Rf, equal to the source resistance, Rs, in the feedback path.

The voltage drop created by I1across the added resistor subtracts from the –I2R2 output error voltage.

If I1 = I2, then the output voltage is zero.

Usually they are not equal, but even then the output voltage error is reduced, since the input offset current, IOS, is less than I2:

OUT(error) = |I1 – I2|Rs = IOSRs

Bias current compensation in other op-amp configurations

In a noninverting amplifier we add a resistor Rc.

The compensating resistor value equals the parallel combination of Ri and R­f.

The input creates a voltage drop across Rc that offsets the voltage across the combination or Rf and Ri.

Thus, the output is reduced.

The same is done for the inverting amplifier.

Input offset voltage compensation

The output voltage of an op-amp when the differential input is zero should be also zero.

However, due to unavoidable internal imbalances and due to non-zero bias currents, a small voltage, VIO, is seen between the terminals.

ICs provide a means to compensate for this.

This is generally done by connecting an external potentiometer to pins designated with Offset Null.

With zero input voltage, the output is set to zero by adjusting the potentiometer.

The pinout for the 741 op-amp (the most common op-amp IC) is shown next.

Op-amps With Negative Feedback

Op-Amps with negative feedback

There are several basic ways in which an op-amp can be connected using negative feedback to stabilize the gain and increase frequency response.

The large open-loop gain of an op-amp creates instability because a small noise voltage on the input can be amplified to a point where the amplifier is driven out of the linear region.

Open-loop gain varies between devices.

Closed-loop gain is independent of the open-loop gain.

Closed-Loop voltage gain, Acl

It is the voltage gain of an op-amp with external feedback.

Gain is controlled by external components.

Noninverting Amplifier

The op-amp circuit shown below is a non-inverting amplifier in a closed-loop configuration.

Input signal is applied to the non-inverting input.

The output is applied back to the inverting input through feedback (closed loop) circuit formed by the input resistor Ri and the feedback resistor Rf.

This creates a negative feedback.

The two resistors create a voltage divider, which reduces Vout and connects the reduced voltage Vf to the inverting input.

The feedback voltage is:

Vf = Ri/(Ri + Rf)Vout

The difference between the input voltage and the feedback voltage is the differential input to the op-amp.

This differential voltage is amplified by the open loop gain, Aol, to get Vout­.

Vout­ = Aol(Vin – Vf)

Let B = Ri/(Ri + Rf). Thus Vf = BVout and

Vout = Aol(Vin – BVout)

Manipulate the expression to get:

Vout = AolVin - AolBVout

Vout + AolBVout = AolVin

Vout(1 + AolB) = AolVin

Overall Gain = Vout/Vin = Aol/(1 + AolB)

Since AolB >> 1, the equation above becomes:

Vout/Vin = Aol/(AolB) = 1/B

Thus the closed loop gain of the noninverting (NI) amplifier is the reciprocal of the attenuation (B) of the feedback circuit (voltage-divider).

Acl(NI) = Vout/Vin = 1/B = (Ri + Rf)/Ri

Finally:

Acl(NI) = 1 + Rf/Ri

Notice that the closed loop gain is independent of the open-loop gain.

Example

Determine the gain of the amplifier circuit shown below. The open loop gain of the op-amp is 150000.

Solution

This is a noninverting amplifier op-amp configuration. Therefore, the closed-loop voltage gain is

Acl(NI) = 1 + Rf/Ri = 1 + 100 k?/4.7 k? = 22.3

Voltage-Follower (VF)

Output voltage of a noninverting amplifier is fed back to the inverting input by a straight connection.

The straight feedback has a gain of 1 (i.e. there is no gain).

The closed-loop voltage gain is 1/B, but B = 1. Thus, the Acl(VF) = 1.

It has very high input impedance and low output impedance.

Inverting Amplifier (I)

The input signal is applied through a series input resistor Ri to the inverting input.

The output is fed back through Rf to the same input.

The noninverting input is grounded.

For finding the gain, let’s assume there is infinite impedance at the input (i.e. between the inverting and non-inverting inputs).

Infinite input impedance implies zero current at the inverting input.

If there is zero current through the input impedance, there is NO voltage drop between the inverting and noninverting inputs.

Thus, the voltage at the inverting input is zero!

- The zero at the inverting input is referred to as virtual ground.

Since there is no current at the inverting input, the current through Ri and the current through Rf are equal:

Iin = If.

The voltage across Ri equals Vin because of virtual ground on the other side of the resistor. Therefore we have that

Iin = Vin/Ri.

Also, the voltage across Rf equals –Vout, because of virtual ground. Therefore:

If = -Vout/Rf

Since If = Iin, we get that:

-Vout/Rf = Vin/Ri

Or, rearranging,

Vout/Vin = -Rf/Ri

So,

Acl(I) = -Rf/Ri

Thus, the closed loop gain is independent of the op-amp’s internal open-loop gain.

The negative feedback stabilizes the voltage gain.

The negative sign indicates inversion.

Full-wave rectifiers circuit

Half-wave rectifiers have some applications.

However, full-wave rectifiers are the most commonly used ones for dc power supplies.

A full-wave rectifier is exactly the same as the half-wave, but allows unidirectional current through the load during the entire sinusoidal cycle (as opposed to only half the cycle in the half-wave).

Average value of output becomes twice that of the half wave rectifier output:

VAVG = 2Vp/p

There are two main types of full wave rectifiers:

i) Center-tapped full-wave rectifier.

Two diodes connected to the secondary of a center-tapped transformer.

Half of Vin shows up between the center tap and each secondary.

At any point in time, only one of the diodes is forward biased.

This allows for continuous conduction through load.

Note that the peak inverse voltage (PIV) across D2 is:

PIV = (Vp(sec)/2 – 0.7) – (-Vp(sec)/2)

= (Vp(sec)/2 + Vp(sec)/2 – 0.7)

= Vp(sec) – 0.7

Since Vp(out) = Vp(sec)/2 – 0.7, we get:

Vp(sec) = 2Vp(out) + 1.4

Thus, the PIV across each diode becomes:

PIV = 2Vp(out) + 0.7 V

ii) Bridge full-wave rectifier.

When the input cycle is positive, diodes D1 and D2 are forward biased.

When the input cycle is negative, diodes D3 and D4 are the ones conducing.

The output voltage becomes:

Vp(out) = Vp(sec) – 1.4 V

The reason we’d rather use a full bridge rectifier than a center-tap, is that the PIV is a lot smaller:

PIV = Vp(out) + 0.7 V

Automatic 12V Lead Acid Battery Charger




Parts

Part
Total Qty.
Description
Substitutions
R1, R32330 Ohm 1/4W Resistor
R21100 Ohm 1/4W Pot
R4, R5, R7, R8482 Ohm 2W Resistor
R61100 Ohm 1/4W Resistor
R911K 1/4W Resistor
C11220uF 25V Electrolytic Capacitor
D11P600 DiodeAny 50V 5A or greater rectifier diode
D211N4004 Diode1N4002, 1N4007
D315.6V Zener Diode
D41LED (Red, Green or Yellow)
Q11BT136 TRIAC
Q21BRX49 SCR
T1112V 4A TransformerSee Notes
F113A Fuse
S11SPST Switch, 120VAC 5A
MISC1Wire, Board, Heatsink For U1, Case, Binding Posts or Alligator Clips For Output, Fuse Holder


Notes

  1. R2 will have to be adjusted to set the proper finish charge voltage. Flooded and gel batteries are generally charged to 13.8V. If you are cycling the battery (AGM or gel) then 14.5V to 14.9V is generally recommended by battery manufacturers. To set up the charger, set the pot to midway, turn on the charger and then connect a battery to it's output. Monitor the charge with a voltmeter until the battery reaches the proper end voltage and then adjust the pot until the LED glows steadily. The charger has now been set. To charge multiple battery types you can mount the pot on the front of the case and have each position marked for the appropriate voltage.
  2. Q1 will need a heatsink. If the circuit is mounted in a case then a small fan might be necessary and can generally be powered right off the output of D1.
  3. T1 is a transformer with a primary voltage appropriate to your location (120V, 220V, etc.) and a secondary around 12V. Using a higher voltage secondary (16V-18V) will allow you to charge 16V batteries sometimes used in racing applications.
  4. If the circuit is powered off, the battery should be disconnected from it's output otherwise the circuit will drain the battery slowly.
source: aaroncake.net

12V to 120V Inverter circuit



Parts

Part
Total Qty.
Description
Substitutions
C1, C2268 uf, 25 V Tantalum Capacitor
R1, R2210 Ohm, 5 Watt Resistor
R3, R42180 Ohm, 1 Watt Resistor
D1, D22HEP 154 Silicon Diode
Q1, Q222N3055 NPN Transistor (see "Notes")
T1124V, Center Tapped Transformer (see "Notes")
MISC1Wire, Case, Receptical (For Output)


Notes

  1. Q1 and Q2, as well as T1, determine how much wattage the inverter can supply. With Q1,Q2=2N3055 and T1= 15 A, the inverter can supply about 300 watts. Larger transformers and more powerful transistors can be substituted for T1, Q1 and Q2 for more power.
  2. The easiest and least expensive way to get a large T1 is to re-wind an old microwave transformer. These transformers are rated at about 1KW and are perfect. Go to a local TV repair shop and dig through the dumpster until you get the largest microwave you can find. The bigger the microwave the bigger transformer. Remove the transformer, being careful not to touch the large high voltage capacitor that might still be charged. If you want, you can test the transformer, but they are usually still good. Now, remove the old 2000 V secondary, being careful not to damage the primary. Leave the primary in tact. Now, wind on 12 turns of wire, twist a loop (center tap), and wind on 12 more turns. The guage of the wire will depend on how much current you plan to have the transformer supply. Enamel covered magnet wire works great for this. Now secure the windings with tape. Thats all there is to it. Remember to use high current transistors for Q1 and Q2. The 2N3055's in the parts list can only handle 15 amps each.
  3. Remember, when operating at high wattages, this circuit draws huge amounts of current. Don't let your battery go dead :-).
  4. Since this project produces 120 VAC, you must include a fuse and build the project in a case.
  5. You must use tantalum capacitors for C1 and C2. Regular electrolytics will overheat and explode. And yes, 68uF is the correct value. There are no substitutions.
  6. This circuit can be tricky to get going. Differences in transformers, transistors, parts substitutions or anything else not on this page may cause it to not function.
  7. If you want to make 220/240 VAC instead of 120 VAC, you need a transformer with a 220/240 primary (used as the secondary in this circuit as the transformer is backwards) instead of the 120V unit specified here. The rest of the circuit stays the same. But it takes twice the current at 12V to produce 240V as it does 120V.
source: aaroncake.net

Circuit of 12V To 24V DC-DC Converter


Part
Total Qty.
Description
Substitutions
R1, R2, R3, R4, R8, R76100K 1/4W Resistor
R51470 Ohm 1/2W Resistor
R6110K Linear Pot
C110.01uF Mylar Capacitor
C210.1uF Ceramic Disc Capacitor
C31470uF 63V Electrolytic Capacitor
D111N4004 Rectifier Diode
D21BY229-400 Fast Recovery DiodeSee Notes
Q11BC337 NPN Power Transistor
U11LM358 Dual Op Amp IC
L11See Notes
MISC1Board, Wire, Socket For U1, Case, Knob For R6, Heatsink for Q1

Notes

  1. R6 sets the output voltage. This can be calculated by Vout = 12 x (R8/(R8+R7)) x (R6B/R6A).
  2. L1 is made by winding 60 turns of 0.63MM magnet wire on a toroidial core measuring 15MM (OD) by 8MM (ID) by 6MM (H).
  3. D2 can be any fast recovery diode rated at greater then 100V at 5A. It is very important that the diode be fast recovery and not a standard rectifier.
  4. Q1 will need a heatsink.

circuit of Adjustable Strobe Light

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Part
Total Qty.
Description
Substitutions
R11250 Ohm 10 Watt Resistor
R21500K Pot
R31680K 1/4 Watt Resistor
D1, D221N4004 Silicon Diode
C1, C2222 uF 350V Capacitor
C310.47uF 400 Volt Mylar Capacitor
T114KV Trigger Transformer (see "Notes")
L11Flash Tube (see "Notes")
L21Neon Bulb
Q11106 SCR
F11115V 1A Fuse
MISC1Case, Wire, Line Cord, Knob For R2

Notes

  1. T1 and L1 are available from The Electronics Goldmine (see Where To Get Parts).
  2. This ciruits is NOT isolated from ground. Use caution when operating without a case. A case is required for normal operation. Do not touch any part of the circuit with the case open or not installed.
  3. Most any diodes rated at greater then 250 volts at 1 amp can be used instead of the 1N4004's.
  4. Do not operate this circuit at high flash rates for more than about 30 seconds or else C1 and C2 will overheat and explode.
  5. There is no on/off switch in the schematic, but you can of course add one.
source: aaroncake.net

circuit of 40W Fluorescent Lamp Inverter


Parts

Part
Total Qty.
Description
Substitutions
R11180 Ohm 1W Resistor
R2147 Ohm 1/4W Resistor
R312.2 Ohm 1W Resistor (only needed once)
C1, C22100uF 16V Electrolytic Capacitor
C31100nF Ceramic Disc Capacitor
Q11TIP 3055 or 2N3055 or equivalent
L11See "Notes"
T11See "Notes"
MISC1Wire, Case, Board, Heatsink For Q1, heatshrink, AM antenna rod for coil

Notes

  1. Email Bart Milnes with questions, comments, etc.
  2. Wind L1/T1. You will need an AM antenna rod that is about 60mm (2.5 inches) long to wind T1/L1 on. T1/L1 are wound on the same core. Shrink a layer of heatshrink over the core to insulate it. Leave 50mm of wire at each end of the coils.
    Primary: Wind 60 turns of 1mm diameter enamelled copper wire on the first layer and put a layer of heatshrink over it.
    Feedback: Wind 13 turns of 0.4mm enamelled copper wire on the core and then heatshrink over that.
    Secondary: This coil has 450 turns of 0.4mm enamelled copper wire in three layers. Wind one layer and then heatshrink over it. Do the same for the next two.
    Transformer/Inductor Winding
  3. Calibrate/test the circuit. To calibrate/set up the circuit connect the 2.2 Ohm 1W resistor (R3) in series with the positive supply. Connect a 40W fluorescent tube to the high voltage ends of the transformer. Momentarily connect power. If the tube doesn't light immediately reverse the connections of L1. If the tube still doesn't work, check all connections. When you get the tube to light remove the 2.2 ohm resistor and the circuit is ready for use. You will not need R3 again.
  4. This circuit is designed for 220V lamps. It will work with 120V units just fine, but will shorten the life of the tube.
  5. This page has been extensively rewritten by Bart Milne. (15/3/01)
source:www.aaroncake.ne

circuit of 3 Channel Spectrum Analyzer

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Parts

Part
Total Qty.
Description
Substitutions
R11100K 1/4W Resistor
R21820K 1/4W Resistor
R3, R14, R16, R1842.2 Meg 1/4W Resistor
R4, R5, R6322K Pot
R7, R8, R9, R25, R27, R29610K 1/4W Resistor
R10, R11, R123680 Ohm 1/4W Resistor
R13. R15, R173580K 1/4W Resistor
R19, R20, R21339K 1/4W Resistor
R22, R23, R24347K 1/4W Resistor
R26, R28, R30333 Ohm 1/4W Resistor
C1, C5, C630.012uF Polystyrene Capacitor
C2, C9, C10, C1143.3uF Electrolytic Capacitor
C3, C420.0022uF Polystyrene Capacitor
C7, C8247nF Polystyrene Capacitor
C12, C13, C1430.47uF Electrolytic Capacitor
C15, C16, C17322uF Electrolytic Capacitor
D1, D2, D331N4002 Silicon Diode
D4, D5, D6, D8, D85Green LED
D10, D11, D12, D13, D145Amber LED
D16, D17, D18, D19, D205Red LED
U11LM3900 Quad Op Amp
U2, U3, U43AN6884 Bar Graph IC
MISC1Board, Wires, Sockets For ICs

Notes

  1. The circuit expects line level inputs. If you connect it to speaker level, you will have to readjust the circuit every time you change the volume.
  2. After the circuit is connected, apply power and signal. Now adjust the pots until the corresponding group of LEDs reacts.

circuit of 12VDC Fluorescent Lamp Driver


Part
Total Qty.
Description
Substitutions
C11100uf 25V Electrolytic Capacitor
C2,C320.01uf 25V Ceramic Disc Capacitor
C410.01uf 1KV Ceramic Disc Capacitor
R111K 1/4W Resistor
R212.7K 1/4W Resistor
Q11IRF510 MOSFET
U11TLC555 Timer IC
T116V 300mA Transformer
LAMP14W Fluorescent Lamp
MISC1Board, Wire, Heatsink For Q1

Notes

  1. Q1 must be installed on a heat sink.
  2. A 240V to 10V transformer will work better then the one in the parts list. The problem is that they are hard to find.
  3. This circuit can give a nasty (but not too dangerous) shock. Be careful around the output leads.

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