Circuit Wiring Solution: control

Showing posts with label control. Show all posts

Wednesday, October 29, 2014

Low voltage DC motor speed control circuit using TDA7274

Description.
Here is the circuit diagram of a low voltage /low power DC motor speed controller based on the IC TDA 7274 from ST Microelectronics. The IC TDA 7274 is a monolithic integrated DC motor speed controller intended for low voltage/ low power applications. Built in internal voltage reference voltage, wide input voltage range (1.8 t0 6V), high linearity, 700mA output current, excellent temperature stability etc make this IC well suitable for almost all low power DC motor speed control applications.
The motor to be controlled is connected between pin3 (Vs) and pin4 (output) of the IC. Resistor network comprising of R1, R2, and R3 is the section that deals with the speed control. Control pin (pin8) of the IC is connected to the junction of R2 and R3 and the speed of the motor varies linearly according to the position of POT R3. Capacitor C1 rectifies the fluctuations in motor speed and capacitor C2 cancels the motor spikes.

Notes.
The circuit can be assembled on a Perf board.
Power supply Vs can be anything between 1.8V to 6V and it must be selected according to the rating s of the motor.
Maximum output current capacity of this circuit is 700mA.
TDA7274 must be mounted on a holder.
POT R3 can be used to vary the motor speed

Friday, October 24, 2014

3 Band Tone Control Circuit

3 Band Tone Control circuit uses an op-amp as an amplifier end. Tone Control circuit is a regulator of tone bass, midrange and treble or 3 band called because it can set the three tones. Filter circuit is applied to the series of "Tone Control 3 band" This type baxandal like the title of this article.

Results filtering regulator tone or tone control baxandal type is good, because there is no signal level is wasted directly into the ground. Range frequency tones generated from Tone Control 3 band was determined by the configuration of the R and C of the filter section baxandal. As an amplifier on Tone Control The set of three band use traditional IC LF351 has slewrate high and high input impedance. For more details, series 3 Band Tone Control as follows.

Figure Series 3 Band Tone Control

3 Band Tone Control circuit above using LF351 Op-Amp is used to strengthen the signal after filtering by the filter process baxandal. Level tone Bass, Midrange and Treble settings are determined by potensio R1, R2 and R3. Frequency filter in the circuit above baxandal to 50 Hz bass tone, tone Midrange 1 KHz and 10 KHz for Treble tone.

Sunday, October 5, 2014

Bass and Treble Control Circuit Diagram

This bass and treble controllercircuit is based on the classicBaxandall tone control circuitry and provides a maximum cut and boost of around 10dB at 10kHz and 50Hz. The first stage that is built aroundBC109C transistor acts as a buffer and provides the circuit with a high input impedance at around 250kΩ. The gain of the stage is nearly unity. Since the Baxandall tone control circuit is a passive design, all frequencies are amplified. The position of the boss and treble control potentiometers and reactance of the capacitors affect the audio response. Second BC109C transistor provides about triple boost. The potentiometers should be linear type. The output of the circuit can drive an amplifier with input impedance of 10kΩ to 250kΩ.

Saturday, September 20, 2014

Circuit diagram capacitor charge control

The scheme is designed to protect against inrush current when the battery uncharged capacitor on-board network. Who has not tried to include uncharged faradnik network without limiting resistor - better not ... At a minimum, get burnt contacts.

When you turn the discharged capacity in network capacity C1 is discharged, T1 (n-MOSFET switch with low channel resistance) is closed.Capacitance C2 (the same faradnik) is charged through a low-resistance R5. T2 opens almost instantly, the shunt to ground C1 and T1 gate.When the potential negative terminal C2 falls below 1V (charge to Uakb - 1B), T2 closes smoothly C1 is charged to about 9/10 Uakb opening T1. The time constant R2C1 is large enough so that the current surge T1 (pre-charge C2 +1 V to Uakb) does not exceed the rating for T1.

In the future, the negative terminal of C2 constantly shorted to ground through T1, regardless of the direction CURRENT T1 (both literally - from drain to source, and in the opposite direction). Nothing wrong with "rollover" OPEN TIR transistor not. When choosing a good enough conductive transistor entire reverse current flow through the channel, and a built-wheeling diode will not open because the voltage drop across the channel at times less than required for the opening of 0.5-0.8 V. By the way, there is a whole class of TIR devices (eg FETKY ), designed specifically to work in the opposite direction (synchronous rectifiers), they have built a diode is shunted by an additional force Schottky diode.

Calculation: for transistor IRF1010 (Rds = 0.012 ohms) voltage drop of 0.5 ohms will only be achieved with the current channel 40A (P = 20W).For four of these transistors in parallel and the same discharge current of 40A - on each transistor will dissipate 0,012 * (40/4) ^ 2 = 1.2 W, ieradiators they are not required (the more that will dissipate 1.2W only when differential current consumption but not consistently).

Dense installation (you have plenty of space for extra radiator?) - Advisable parallels small (body TO251, DIP4) transistors, generally do not provide radiators, based on the ratio of current (power) consumption of the amplifier - Rds - limit power dissipation. Since Pds max is typically 1W (800 mW for DIP4), the number of n transistors (c Rds each) for the amplifier with an output power Pout must be at least n> 1/6 * Pout * sqrt (Rds) at 12V supply (dimension in the formula I omitted). In fact, given the short duration current pulses, n can be easily reduced by half compared with a given formula.

Resistor R5 is selected from the charge compromise heat output and charging time. When these 22 ohms - charge time of about 1 minute at power dissipation 7 watts. R5 can instead include 12V bulb, say, indicator. Resistors R1, R3 - reinsurance (discharged capacity when disconnected from the network).

Connect to indicate activation of additional inverter (reducing R2). Attention! The scheme is efficient at using npn transistors T2, T3 with h21e> 200 (KT3102). Depending on the brightness of the LED, R1, select the range of 200 ohms - 1k.

But the view of the circuit in which the key shutter control signal REMOTE (And transistor). The non-connected or off REMOTE key transistor guaranteed closed. D3-D4 LEDs indicate charging C1, D5-D6 - the open state of the key.

Accurate indication of the threshold voltage is provided easiest IP TL431 (KR142EN19) in a typical mode voltage comparator (with the corresponding subgroup in the input circuit and current-limiting circuit cathode R).

Loss schemes largely depend on the installation. Ensure that the minimum resistance (and corresponding current thickness of the wires) in the power circuit (terminal + / C2 / T1 /-terminal). In amateur practice, I think, make outgoing terminals impractical - it is better to unsolder the short wires AWG8, which binds to the terminal block diagram of the amplifier.

Original article source cxem.net

Tuesday, September 9, 2014

Test Transmitter for Radio Control Wiring diagram Schematic

This schema is ideal for those with radio transmitting equipment in the control frequency of 35 or 40 MHz, it is a field strength meter, it can check the output power of the transmitters, so you can detect any problems even before the equipment is used. For the test and verification of the correct operation of the transmitter R / C, it must 3 or 4 LEDs lit at a distance of 10 meters.

The length adjustment of the antenna will allow the gauge to operate at a shorter distance.L1 must be initially set to the maximum number of lighting LEDs in a distance of 10 meters or more. Toko coil used in the schema is no longer manufactured but the coil can be constructed at a frequency of 40Mhz.

Test Transmitter for Radio Control Circuit Diagram

Friday, September 5, 2014

4 W audio power amplifier with DC volume control

GENERAL DESCRIPTION:

The TDA1013B is an integrated audio amplifier circuit with DC volume control, encapsulated in a 9-lead single in-line (SIL) plastic package. The wide supply voltage range makes this circuit ideal for applications in mains and battery-fed apparatus such as television receivers and record players. The DC volume control stage has a logarithmic control characteristic with a range of more than 80 dB; control is by means of a DC voltage variable between 2 and 6.5 V. The audio amplifier has a well defined open loop gain and a fixed integrated closed loop. This device requires only a few external components and offers stability and performance. 4 W audio power amplifier with DC volume control

Features:

Few external components

Wide supply voltage range

Wide control range

Pin compatible with TDA1013A

Fixed gain

High signal-to-noise ratio

Thermal protection

PINNING:

power ground

amplifier output

supply voltage

electronic filter

amplifier input

control unit output

control voltage

control unit input

signal ground (substrate)

Circuit Diagram

4 W audio power amplifier with DC volume control

Datasheet for TDA1013B: Download

Friday, August 22, 2014

External Winamp Control

Nowadays, winamp have full support to keyboard shortcuts. But some time ago, when Winamp didn’t have this feature, I was thinking in a way I could change the music just by pressing one button, it would make things faster and easier to change songs, specially during games. So I decided to make a external control to it. I found one winamp plugin that shows how to configure a external control using the Serial Port, being able to make 4 or 15 buttons control. I decided to make this, step-by-step, how to do it, hope you enjoy.

Material:

4 push-buttons
SERIAL connector
Connector Box
Cable

Necessary tools:

Soldering iron and accessories

You can put the buttons wherever you want, I decided to put mine in one old diskbox.
I decided to use a network cable to connect the Serial connector to the buttons, because its easier to organize and makes the work simplier and faster.

The scheme:

Making the control:

Looking in the scheme, we see that we have to connect one side of each buttons to one cable, these will be solded in the pin number 4.

After have done the soldering in one side of each button, you must then connect the other side with a cable that goes to the pins of the serial, now however is important that they are connected with the indicated pins (Just follow the scheme) .
Here you can see a picture of my work until now, it looks quite ugly I know, sorry.

Configuring the Software

You must set the COM port you are using, usually normal computers have up to 2 ports, so just select the one you plugged the control.
Select the number of buttons your control have. (In this HowTo, we’d choose the “4 buttons”)
Now you must remap the buttons, its now the time when you’ll see if everything is working. If you are able to remap all the buttons, congrats, its working!!
Its ready, now the last step, you have to configurate what you want the buttons to do. This can be found in the “WINAMP” of the program. There you can setup many different options, like Volume Up, Volume Down, Next Song, Previous Song.
One cool stuff is there in “Type:”, where you can configure the way you wanna the buttons pressing to respond.
Click: Just one click to make it work. Can work with one or double-click.
Down/Up: This will activate the option when you press and a different one when you release the buton.
Turbo: Here you can configure the options for holding the button, usually used for Volume Up and Down.
Clicks + Turbo: You can configure “Clicks” and “Turbo”Option at the same time
Clicks + Hold: You can configure “Clicks” and “Hold” Option at the same time

In the end, I put the buttons in that disk case I told before, and this are the results:

I don’t know if I was clear enought in this HowTo, I will re-check this sometime.
If you liked this, have any correction or advice, please leave a comment!

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