Showing posts with label with. Show all posts
Showing posts with label with. Show all posts
Tuesday, October 28, 2014
Transistor Checker with 555 Timer 4027IC
This regular circuit has helped me prohibited on many occasions. It is able to check transistors, inside the circuit, down to 40 ohms across the radio dish-foot otherwise base-emitter junctions. It can in addition check the output power transistors on amplifier circuits. Circuit company is because follows. The 555 timer ( IC1 ) is usual up as a 12hz multi vibrator. The output on pin 3 drives the 4027 flip-dud ( IC2). This flip-flop divides the input frequency by two and delivers complementary voltage outputs to pin 15 and 14. The outputs are connected to LED1 and LED2 through the current limiting resistor R3.
The LEDs are arranged so to facilitate what time the polarity across the circuit is lone way single one LED force light and what time the polarity reverses the other LED will light, therefore while rebuff transistor is connected to the tester the LEDs will alternately flicker. The IC2 outputs are too connected to resistors R4 and R5 with the junction of these two resistors connected to the immoral of the transistor being tested. With a proficient transistor connected to the tester, the transistor yearn for circle on and crop a passing across the LED duo. If a good NPN transistor is connected next LED1 will burst by itself and if a good PNP transistor is connected then LED2 will flash by itself. If the transistor is initiate both LEDs force flash and if the transistor is shorted at that moment neither LED will flash.
Monday, October 27, 2014
Converter with 2N3055 transistors
This plain converter using a Zener diode and a transistor into a 9V DC 12V DC battery power to the most 1A. The circuit is very simple to build, and requires just 3 electronic components, resistors, zener diodes and transistors. The 2N3055 transistors, 1N4738A Zener diode before Zener voltage and the same power. 3W, and perhaps wire wound resistor 3R type. Powering a expedient tool to avail yourself of 9V DC.
Read More..
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| Converter with 2N3055 transistors |
The output voltage of the following formula:
Zener voltage Vout = + 0.65V, 0.65V, which is the heart-emitter voltage of transistors
Friday, October 24, 2014
Build a Wire Break Alarm With Delay Circuit Diagram
Here is a simple circuit of wire-break alarm that activates after a delay of 15 to 30 seconds. When the thin-wire loop running across the entrance door is broken, the alarm sounds after a delay of 15 to 30 seconds, the time period set through VR1. Thus the occupants get sufficient time to lock the room from the outside and catch the thief.
The circuit uses CD4060, which is a 14-stage ripple-carry binary counter/divider and oscillator. It is wired as a timer here and does not need input pulse for trigger. CD4060 gets activated as soon as the power supply is switched on. Output O13 of CD4060 goes high after the lapse of preset delay set through VR1. Transistor SL100 (T2) is wired as a switch to power the timer section built around CD4060. When the wire loop is closed, transistor T2 does not conduct. So power to the timer circuit is not available and the piezobuzzer does not sound.
Wire-Break Alarm With Delay Circuit Schematic
On the other hand, when the wire loop is broken by some intruder, transistor T2 conducts to power the circuit and the piezobuzzer sounds after 15 to 30 seconds. IC1 can be reset by connecting the wire loop or interrupting the supply. The circuit works off regulated 9V-12V. Assemble it on a general-purpose PCB and enclose in a metallic or plastic box of appropriate size. Connect piezobuzzer PZ1 through external wires and complete the installation.
Thursday, October 23, 2014
VCO 1 2GHz With Linear Modulation
Since high frequency voltage-controlled oscillators, or VCOs, are not easy to construct, Maxim (www.maxim-ic.com) has produced an integrated 1.2GHz oscillator, the MAX2754. The center frequency is set using the TUNE input, and a linear modulation input allows the frequency to be modulated. The IC is available in an 8-pin µMAX package, operates from a supply of between 2.7 V and 5.5 V, and draws a current of less than 2 mA. Both TUNE and MOD operate over control voltage range of +0.4 V to +2.4 V. TUNE allows the VCO frequency to be adjusted from 1050 MHz to 1270 MHz. In some applications a PLL control voltage will be applied here, allowing the center frequency to be set exactly to a desired value.
For simplicity in the circuit diagram we have shown a potentiometer. The MOD input allows the VCO to be modulated in a digital or analogue fashion, with a transfer slope of –500 kHz/V. In the circuit we have shown an example where MOD is used for frequency shift keying (FSK) modulation. Resistors R1 to R4 shift the level of the data signal so that it has a center value of +1.4 V and an amplitude corresponding to the desired frequency deviation. One example set of values, suitable for use with a 5 V power supply, is as follows: R1 = 480 ?, R2 = 100 ?, R3 = 220 ? und R4 = 270
Monday, October 20, 2014
24V DC Powered Beeper with 4 Separate Inputs
24v DC is a very popular voltage used in industrial settings. This hobby circuit below was designed to accept four different 24v DC alarm input signals, which are then used to drive a single low power beeper. The beeper is a magnetic type with its own oscillator/driver. The four diodes form an “OR” gate so any one of the four inputs will cause the beeper to make noise. A CMOS version of the popular 555 timer is used to strobe the beeper on and off at about 1Hz.
Copyright: Discover Circuits
Friday, October 17, 2014
Designing A Li Ion Battery Charger with Load Sharing MCP73837
Batteries often serve as the main energy source for portable electronic devices. Although they depend on batteries, portable consumer electronic products, such as GPS devices and multi-media players, often consume energy directly from an ac-dc wall adapter or accessory power adapter (or “Auto Adapter”) when the battery is low or the device is in a stationary mode. Due to their cost effectiveness over their useful life, rechargeable batteries are often used for the power source of the portable electronic device.
Attributes such as “relatively high energy density” and “maintenance free” make Lithium-Ion (Li-Ion) batteries popular in the portable consumer electronic products. Refer to the application note, AN1088, “Selecting the Right Battery System For cost Sensitive Portable Applications While maintaining Excellent Quality” (DS01088) for characteristics of Li-Ion batteries. Some examples of how to properly design with Li-Ion batteries will be discussed in this application note.
Wednesday, October 15, 2014
Build a Theremin with Inverter Gates
This simple but complete Theremin with Inverter Gates is constructed using only two inverter chip plus one regulator IC. This Theremin circuit consist of five functional blocks: power supply regulator, hand controlled oscillator, null oscillator, mixer, and filter. Here is the complete schematic diagram.
Theremin with Inverter Gates schematic diagram
Voltage Regulator and Circuit Protector
The power supply regulator consist of LP2950 regulator IC, which stabilize the voltage from battery to 5V. You can use more popular 7805 IC for this, but since the power consumption of this Theremin circuit is very small, then you can use 78L05 which is smaller. CR1 diode is used to protect from inappropriate battery polarity, shorting the battery voltage together with R8 100 Ohm resistor which prevent the large current when the battery is installed in wrong direction. Although the inverter chip will work well for 9V battery, there is a benefit of using voltage regulation to regulate the battery voltage at lower voltage level, that the voltage will remain constant for until the end of battery life. This will avoid frequency drift of the Theremin’s null oscillator which should be carefully adjusted to zero the output frequency, which can be affected by the supply voltage.
Hand Controlled Oscillator
The hand proximity sensor is an oscillator which has antenna extension which shift the capacity coupling in the loop. This capacitance shift occur when we move our hand approaching the antenna. Since this change is very small in percentage, we need this oscillator to be high enough to produce notable frequency difference. This oscillator block is built around U1A, U1B, and U1C. This oscillator give oscillation at around 73kHz. This frequency is not directly audible, we have to process this signal further to produce audible signal.
Null Oscillator
Null oscillator is employed to produce a constant frequency oscillation that will be used to produce differential frequency which is audible. This oscillator block is built around U2A, U2B, and U2C. This null oscillator should be adjustable to set the null point where the Theremin should produce no oscillation at certain hand position. At this point, the null oscillator should be adjusted to have same frequency with the hand controlled oscillator since the audible Theremin output is the product of the difference between hand controlled and null oscillator frequencies.
Frequency Mixer (Differentiator)
The mixer is used to mix the signal from two oscillators, the hand controlled and the null oscillators. This mixer produce an output which contain many frequency components, not only the difference but also the original and the sum, since the amplifier U1F is basically a digital inverter which has non-linear transfer function. Fortunately, all the frequency components, except the difference, will be much higher than the needed signal and inaudible. This make it easy to remove by simple low pass filter to obtain only the differential frequency component.
Low Pass Filter
As stated before, we need to obtain only the audible frequency component by low-pass filtering. Although the high frequencies is inaudible, we still have to remove it since it can cause damage in audio power amplifier is the level is too high. It can distort the audible signal, and it can eat the electric power like ghost, frying your amplifier or at least make it overheated. This Theremin circuit use simple low pass filter consist of C4, R5, and R7 for the passive stage, and C2 inside the inverter amp loop.
Friday, October 3, 2014
60 Watt Guitar Amplifier with Tone Control
The following is a circuit of amplifiers are equipped with the suitable regulatory tone in use to strengthen the electric guitar, employing a single-rail supply of regarding 60V and capacitor-coupling for the speaker . the benefits for a guitar amplifier are the terribly simple circuitry, even for comparatively high power outputs, and an explicit built-in degree of loudspeaker protection, owing to capacitor C8, preventing the voltage supply to be conveyed into loudspeakers in case of output transistors failure.
In all cases where Darlington transistors are used because the output devices it is essential that the sensing transistor (Q2) should be in as close thermal contact with the output transistors as potential. thus a TO126-case transistor sort was chosen for straightforward bolting on the heatsink, terribly near the output combine
R30 must be cut so as to live regarding half the voltage supply across the positive lead of C7 and ground. an improved setting is done using an oscilloscope, so as to get a symmetrical clipping of the output wave type at most output power
Note:
To set quiescent current, tide ampare meter in series between supplay with this series, then do the following
- Set the volume control to the minimum and Trimmer R3 to its minimum resistance.
- Power-on the circuit and adjust R3 to read a current drawing of about 30 to 35mA.
- Wait about 15 minutes, watch if the current is varying and readjust if necessary.
List component
R1,R2______________68K 1/4W Resistors
R3________________680K 1/4W Resistor
R4________________220K 1/4W Resistor
R5_________________33K 1/4W Resistor
R6,R16______________2K2 1/4W Resistors
R7__________________5K6 1/4W Resistor
R8,R21____________330R 1/4W Resistors
R9_________________47K 1/4W Resistor
R10_______________470R 1/4W Resistor
R11_________________4K7 1/4W Resistor
R12,R20____________10K 1/4W Resistors
R13_______________100R 1/4W Resistor
R14,R15____________47R 1/4W Resistors
R17,R18,R19_______100K 1/4W Resistors
R22__________________6K8 1W Resistor
R23,R25_____________470R 1/4W Resistors
R24__________________2K 1/2W Trimmer Cermet
R26,R27_______________4K7 1/2W Resistors
R28________________220R 1/2W Resistor
R29__________________2K2 1/2W Resistor
R30_________________50K 1/2W Trimmer Cermet
R31________________68K 1/4W Resistor
R32,R33______________R47 4W Wirewound Resistors
C1,C4,C5,C6________10µF 63V Electrolytic Capacitors
C2_________________47µF 63V Electrolytic Capacitor
C3_________________47pF 63V Ceramic Capacitor
C7_________________15nF 63V Polyester Capacitor
C8_________________22nF 63V Polyester Capacitor
C9________________470nF 63V Polyester Capacitor
C10,C11,C12________10µF 63V Electrolytic Capacitors
C13_______________220µF 63V Electrolytic Capacitor
C14,C15,C17,C18________47µF 63V Electrolytic Capacitors
C16________________100µF 25V Electrolytic Capacitor
C19_________________33pF 63V Ceramic Capacitor
C20_______________1000µF 50V Electrolytic Capacitor
P1,P2______________10K Potentiometers
P3_________________10K Potentiometer
D1,D2____________BAT46 100V 150mA Schottky-barrier Diodes
D3_________________LED
Q1,Q3____________BC546 NPN Transistors
Q2_______________BC556 PNP Transistor
Q4,Q5____________BD139 80V 1.5A NPN Transistors
Q6_____________MJ11016 120V 30A NPN Darlington Transistor
Q7_____________MJ11015 120V 30A PNP Darlington Transistor
J1,J2___________6.3mm. Mono Jack sockets
SW1,SW2___________SPST Switches
SPKR______________speakers 8 or 4 Ohm with Minimum power 75W
Wednesday, September 24, 2014
PCM2902 Soundcard with Microphone Input Schematic
PCM2902 Soundcard with Microphone Input Schematic
Many of us have a pair of headphones connected to the output of the computer sound card us either to enjoy songs, or a game. Very likely your headphones and microphone, which also connect to the appropriate slot your sound card. But at some point broke down the female plug my sound card, and because quite a lot to change the plug when I put the headphones and when the speakers. A small structure is a sound card, USB, with stereo inputs / outputs, button to increase / volume button for volume and mute! When connected Windows will recognize as a sound card! With all the materials to be SMD, the cornered enough and fit into a small plastic box, which by one measure has a cable with USB plug, sound to go acoustic (Left / Right) and condenser microphones.
The supply of (as imagined) is done by the USB port. The heart of the integrated circuit is PCM2902 of Burr-Brown by Texas Instruments. It is stereo 16-bit DAC and ADC, fully compatible with USB 1.1. DAC sampling frequencies are 32, 44.1 and 48 kHz, ADC has 8, 11.025, 16, 22.05, 32, 44.1 and 48 kHz. If you want more sound intensity, you will need to connect TDA 7050 amplifier to audio output.
Monday, September 22, 2014
With Time Delay High And Low Voltage Cut Off
Overview
The power line fluctuations and cut-offs cause damages to electrical appliances connected to the line. It is more serious in the case of domestic appliances like fridge and air conditioners. If a fridge is operated on low voltage, excessive current flows through the motor, which heats up, and get damaged.
The under/over voltage protection circuit with time delay presented here is a low cost and reliable circuit for protecting such equipments from damages. Whenever the power line is switched on it gets connected to the appliance only after a delay of a fixed time. If there is hi/low fluctuations beyond sets limits the appliance get disconnected. The system tries to connect the power back after the specific time delay, the delay being counted from the time of disconnection. If the power down time (time for which the voltage is beyond limits) is less than the delay time, the power resumes after the delay: If it is equal or more, then the power resumes directly.
This circuit has been designed, built and evaluated by me to use as a protector for my home refrigerator. This is designed around readily available semi-conductor devices such as standard bipolar medium power NPN transistor (D313/SL100/C1061), an 8-pin type 741 op-amp and NE555 timer IC. Its salient feature is that no relay hunting is employed. This draw back is commonly found in the proctors available in the market.
The complete circuit is consisting of various stages. They are: - Dual rail power supply, Reference voltage source, Voltage comparators for hi/low cut offs, Time delay stage and Relay driver stage. Lets now look at the step-by-step design details.
Dual rail power supply.
This is a conventional type of power supply as shown in Figure 1. The power is applied through the step-down transformer (230/12-0-12V/500mA). The DC proportional to the charging input voltage is obtained from bridge rectifier. Two electrolytics are there to bypass any spikes present. Bridge is capable of handling currents up to 1 Amp.
Output is given by: -
V(out) = 0.71 X V (secondary)
= 0.71 X 24V
= 17.04 V
(This equation is similar for the negative rail as well)
Circuit diagram
Low voltage cut off op-amp
Figure 2 shows the use of very common and easily available op-amp 741 as a comparator. The op-amp is available in TO-5 and DIP type packing.
Circuit diagram
In this ckt the zener diode D1 and it’s associated resistor R1 are connected to the non-inverting terminal (+ve) of 741 to give the suitable reference voltage. The DC voltage from the sensor is given to the inverting (-ve) terminal through pre-set R2.This is used to set the input level.
When the sensor input is less than Zener voltage the output from the Op-amp remains high and when it is greater than Zener voltage the output goes low. When the sensing voltage is equal to Zener voltage the output of the op-amp is approximately zero.
This phenomenon is used as a decision for switching the relay and to give cutoff in a low voltage situation.
High voltage cut off op-amp
Here the op-amp is used as a inverted amplifier. See Figure 3.Zener and resistor network gives reference voltage to the inverting terminal (-ve) of op-amp. Sensing voltage derived through the 10 K pre-set is given to the non- inverting (+ve) terminal and this sets the high level cut.
When the input DC from the sensor is less than Zener voltage the output of the op-amp is low and vice-versa. When the input DC voltage is equal to the zener voltage, the op-amps output is approximately zero.
Circuit diagram
Time delay
I’ve selected the 555 timer due to following reasons.
1. Timing from microseconds through hours.
2. Ability to operate from wide range of supply voltages.
3. High temperature stability.
4. Easily Available.
5. Its triggering circuit is quite sensitive.
This is basically a monostable. The external timing capacitor C2 is held initially discharged by the timer. The circuit triggers upon receiving a pulse to its pin 2 when the level reaches 1/3 Vcc. Once triggered., the circuit will remain in that state until the set time is elapsed or power to the circuit cuts off. The delayed period in seconds is 1.1 C2.R1 where R1 is in megohms and C2 is in microfarads. In practice, R1 should not exceed 20 M. If you use an electrolytic capacitor for C2, select a unit for low leakage. The time delay may have to be adjusted by varying R1 to compensate for the wide tolerance of electrolytics.
Circuit diagram
Relay Driver
The output from the voltage level detectors cannot directly drive the relay and hence the relay driver is used.
Circuit diagram
The Complete Circuit
Circuit diagram
Under normal operating conditions i.e. when the input voltage is between maximum and minimum limit the output from the both the comparators are low. The transistor Q1 is OFF and the relay is in de-energized (pole connected to N/C pin) state and the output is obtained.
When the input voltage is below or above the limits set by the pre-sets R8 or R9, the output of the Op-Amps goes either low or high and diodes D1 or D2 would be forward biased depending on the situation. Transistor Q1 switches ON and the flow of current from collector to emitter energizes the relay and the output is cutoff.
A small amount of hystersis has been added via feed back resistors R10 & R11 so that the relay turns on when the level falls to a particular value but does not turn again until it raises a substantial amount above this value. Other wise the relay contacts will frequently turn on/off and produce chattering.
Construction Hints
1) I used a piece of varoboard, which has copper strips on one side to mount the components, and housed the entire circuit and the transformer in a discarded ATX PC power supply box.
2) An autotransformer has been used to set the limits. Set the output of the autotransformer to 250V AC and connect it to the primary of transformer T1 (see Figure 1). Then adjust the pre-set R9 such that relay just energizes. This is the high limit. Next set the output of the autotransformer to 200V AC and adjust the pre-set R8 such that the relay energizes. Please note that these are my preferred limits but you may select any range from say 170 to 270V AC.
3) A neon with a suitable resistor could be connected between the AC supply lines as an ON indicator. Alternatively, LED with a current limiting resistor could be connected between the relay coil so when the relay is energized LED will indicate the situation.
Thursday, September 18, 2014
Low Cost Step Down Converter With Wide Input Voltage Range
The circuit described here is mostly aimed at development engineers who are looking for an economical step-down converter which offers a wide input voltage range. As a rule this type of circuit employs a step-down converter with integrated switching element. However, by using a more discrete solution it is possible to reduce the total cost of the step-down converter, especially when manufacturing in quantity. The TL5001A is a low-cost PWM controller which is ideal for this project. The input voltage range for the step-down converter described here is from 8 V to 30 V, with an output voltage of 5 V and a maximum output current of 1.5 A.
When the input voltage is applied the PWM output of IC1 is enabled, taking one end of the voltage divider formed by R1 and R2 to ground potential. The current through the voltage divider will then be at most 25 mA: this value is obtained by dividing the maximum input voltage (30 V) minus the saturation voltage of the output driver (2 V) by the total resistance of the voltage divider (1.1 kΩ). T1 and T3 together form an NPN/PNP driver stage to charge the gate capacitance of P-channel MOSFET T2 as quickly as possible, and then, at the turn-off point, discharge it again.
The base-emitter junction of T3 goes into a conducting state when the PWM output is active and a voltage is dropped across R2. T3 will then also conduct from collector to emitter and the gate capacitance of T2 will be discharged down to about 800 mV. The P-channel MOSFET will then conduct from drain to source. If the open-collector output of the controller is deactivated, a negligibly small current flows through resistor R2 and the base of T1 will be raised to the input voltage level. The base-emitter junction of T1 will then conduct and the gate capacitance of T2 will be charged up to the input voltage level through the collector and emitter of T1.
The P-channel MOSFET will then no longer conduct from drain to source. This driver circuit constructed from discrete components is very fast, giving very quick switch-over times. Diodes D2 and D3 provide voltage limiting for the P-channel MOSFET, whose maximum gate-source voltage is 20 V. If the Zener voltage of diode D2 is exceeded it starts to conduct; when the forward voltage of diode D3 is also exceeded, the two diodes together clamp the gate-source voltage to approximately 19 V. The switching frequency is set at approximately 100 kHz, which gives a good compromise between efficiency and component size.
Finally, a few notes on component selection. All resistors are 1/16 W, 1 %. Apart from electrolytic C1 all the capacitors are ceramic types. For the two larger values (C2 and C5) the following are used:
The base-emitter junction of T3 goes into a conducting state when the PWM output is active and a voltage is dropped across R2. T3 will then also conduct from collector to emitter and the gate capacitance of T2 will be discharged down to about 800 mV. The P-channel MOSFET will then conduct from drain to source. If the open-collector output of the controller is deactivated, a negligibly small current flows through resistor R2 and the base of T1 will be raised to the input voltage level. The base-emitter junction of T1 will then conduct and the gate capacitance of T2 will be charged up to the input voltage level through the collector and emitter of T1.
The P-channel MOSFET will then no longer conduct from drain to source. This driver circuit constructed from discrete components is very fast, giving very quick switch-over times. Diodes D2 and D3 provide voltage limiting for the P-channel MOSFET, whose maximum gate-source voltage is 20 V. If the Zener voltage of diode D2 is exceeded it starts to conduct; when the forward voltage of diode D3 is also exceeded, the two diodes together clamp the gate-source voltage to approximately 19 V. The switching frequency is set at approximately 100 kHz, which gives a good compromise between efficiency and component size.
Finally, a few notes on component selection. All resistors are 1/16 W, 1 %. Apart from electrolytic C1 all the capacitors are ceramic types. For the two larger values (C2 and C5) the following are used:
- C2 is a Murata type GRM21BR71C105KA01 ceramic capacitor, 1 µF, 16 V, X7R, 10 %;
- C5 is a Murata type GRM32ER60J476ME20 ceramic capacitor, 47 µF, 6.3 V, X5R, 10 %. D1 (Fairchild type MBRS340T3) is a 40 V/3 A Schottky diode. Coil L1 is a Würth WE-PD power choke type 744771147, 47 µH, 2.21 A, 75 mΩ.
- T1 (BC846) and T3 (BC856) are 60 V, 200 mA, 310 mW complementary bipolar transistors from Vishay. The TL5001AID (IC1) is a low-cost PWM controller with an open-collector output from Texas Instruments.
Sunday, September 14, 2014
Simple FM transmitter with 2N3904
In this section discuss about the series of mini fm transmitter, with broadcast coverage of about 300-400 meters. when using a 9 volt working voltage, the transmit power of about 300 meters and when using the working voltage 12 volts, the range of about 400-450 meters, depending on the antenna you use.
This scheme of simple fm transmitter
For L1 and L2 windings 5 times the wrap, you can use a pen to fill melilitnya so neat and after lepaslah content of these pens. C5 is used for placement of broadcasting frequencies, can be tuned between 88-108 mhz, to reach further use steering antenna or Yagi antenna.
Part List
C1 = 0.001uF
C2 = 5.6pF
C3 = 10uFC4 = 10uF
C5 = 3 - 18pF Adjustable capacitor
R1 = 270R
R2 = 4.7K
R3 = 10K
R4 = 100K
R5 = 4.7K
R6 = 4.7K
Q1 = 2N2222A
Q2 = 2N3904
L1 = 5 turn
L2 = 5 turn
Saturday, September 13, 2014
140W audio amplifier with IC STK070
By using the above amplifier circuit you can hear the sound quality is quite good by a high output power. Maximum voltage circuit pa approximately 55Volt DC. 70-140W output power with impedance 8Ohm.
Part List
R1 = 10K
R2 = 1K
R3 = 0.4R
R4 = 0.4R
R5 = 4.7R
C1 = 0.015
C2 = 10uF
C3 = 220uF
C4 = 0.15uF
C5 = 220uF
C6 = 47uF
C7 = 0.047uF
U1 = STK050 , STK070
Battery Charger with Temeperature Sensor
Battery with a LM35 temperature sensor on the charger used to monitor the battery temperature is in charge. Battery temperature sensor is needed because the battery temperature will rise at the time in charge. Battery temperature sensor LM35 temperature sensor has high accuracy in monitoring the battery temperature, it is because the temperature sensor LM35 is a temperature sensor that can convert temperature changes into voltage changes linearly.
Battery Charger with Temeperature Sensor
Battery with a LM35 temperature sensor on the charger used to monitor the battery temperature is in charge. Battery temperature sensor is needed because the battery temperature will rise at the time in charge. Battery temperature sensor LM35 temperature sensor has high accuracy in monitoring the battery temperature, it is because the temperature sensor LM35 is a temperature sensor that can convert temperature changes into voltage changes linearly.
At the time of the charge a battery will experience changes in temperature, where the battery temperature will begin to rise when the battery began to fill. To avoid over heat the battery, the battery temperature sensor LM35 temperature sensor is required to terminate the battery charging current to avoid overheating.
| Battery charger with temperature sensor schematic |
On the battery charger circuit temperature sensor with temperature sensor 35 lm above the R1 is used for setting the maximum value of the desired temperature. Therefore, when the temperature was in-charge the battery begins to rise and reach temperatures setup then this series will break the current battery charge.
Friday, September 12, 2014
How Regulator with 2 Photocoupler
Working of Regulator with 2 Photocoupler that is :
- Photocoupler N901 - used as a coupling-off control on the regulator by mikrokontrol. Which is set high and low voltage B + (st-by at the B + voltage is low). Control of the pin-37 POWER mikrokontrol → V610 → VD913 V908 → N901.
- Photocoupler N903 - used to control on-off the regulator of X-ray circuit protector. X-ray protector circuit of flyback → VD451 → VD452 → SCR VS472. If the flyback voltage regulator over the job will automatically be turned off by N903
- To disable the X-ray circuit protector, it can be temporarily removed photocoupler N903 first. In normal conditions the voltage at the transistor V474 should be zero.
| Regulator Schematics |
- Disable by removing the first circuit protectors N903
- Check the voltage of 300V
- Check all transistors
- Check the start voltage of 300V by R909 >> R906 to the base of transistor power regulator
- Check the feedback C910 >> R904 (to oscillate)
Wednesday, September 10, 2014
3 Band Tone Control with LF351
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.
Read moreTuesday, September 9, 2014
USB Soundcard Circuit with PCM2702
You do not need to install drivers for Windows XP and Vista, because the driver is already in the system, XP and Vista. So this series is really plug and play.
| Block Diagram |
Description
The core of this construction is a 16-Bit Stereo Digital-To-Analog Converter with PCM2702 USB interface.
| Schematic diagram USB soundcard |
PCM2702 only requires a few additional components to work. This scheme is not complex. The sound card can be activated directly from the USB port (jumper W1) or from an external power supply (jumper W3). PCM2702 requires two 3.3V power supply (3V-3.6V) and 5V (4.5V-5.5V). I use a fixed output voltage to 3.3V LDO TPS76733Q (IO2) and the output voltage is adjusted to 5V LDO TPS76701Q (IO3).
LDO Both are produced by TI, I use it because there in my drawer. Each LDO The same can be used. IO3 output voltage should be set to slightly lower than the input voltage to enable LDO stabilization is good, in my case the output voltage set to 4.8V. output voltage can be set by the resistor R33 is adjusted. In the case of low power supply, IO3 be shorted by the W3 jumper. Signalizes D3 LED power on.
| PCB line design usb soundcard |
| Layout PCB usb soundcard |
Small ferrite beads are placed before all power pins on the PCM2702 and GND Vbus and USB. Small beads reduce high frequency hum. I have a problem finding SMD ferrite beads small local shops but finally I get some of them from the old hard drive. They are not really necessary, you can use zero ohm resistors instead of them.
Low-pass filter placed in the output signal path to reduce the sampling frequency. OPA2353UA dual op amp configured as two stereo-order low-pass filter. Led diodes D1 illuminates when the PCM2702 play audio data received from the USB bus. Diode D2 Led illuminates when the USB bus audio delay the transmission of data to the PCM2702.
| Installed component USB soundcard |
This circuit works very well. I just had shorted crystal during soldering so that circuit does not work, but after removing the short noise, a sound card to work. I have been tested on Windows 2000, XP and Vista. The electronic circuit works in all the systems mentioned. Driver is in the operating system so that the sound card is ready within a few seconds after you connect the electronic circuit is with a PC / Laptop / Notebook you are in trouble with the sound card / sound card that.
During writing this article I have found that the PCM2702 is now not recommended for new designs, but TI offers a better solution. PCM2704, PCM2705 has the same functions as the PCM2702, but they include an output filter. They were able to push the headphones directly.
Volume and mute can be controlled via the SPI bus in PCM2705 or PCM2704 with pushbuttons in the case. PCM2704 and PCM2705 are in TSSOP28 package. PCM2706 PCM2704 and PCM2707 similar to PCM2705 but in addition they have the I2S bus. PCM2706 and PCM2707 are in a TQFP32 package. I recommend using the new chip (PCM2704 / PCM2705) for the new design an Operating System.
Sunday, September 7, 2014
Doorbell with IC555
All components arranged as in the picture sequence below. Current will flow starting from the source voltage and to the switch. When the switch is closed current will flow through the diode, where diode serves as a switch is closed because it was given forward bias (anode diode is given positive voltage and the cathode is given a negative voltage).
| 2 Tones Doorbel Schematic with IC555 |
Flows will be divided into two to D1 and D2. Flows from D1 (diode 1) will be channeled towards R3 and proceed toward IC555 pin7 and pin 6. Pin 7 (Discharge) serves as an audible tone interval timing, and pin 6 (threshold) to determine the final timing tone, flow at D2 will be divided into three, heading polar capacitors, resistors, and IC555 pin 4. Polar capacitors are capacitors that have poles. The current through the capacitor and R1 polar probe + will go to the speakers. IC555 pin 4 is reset, as the timing interval can be interrupted by giving the reset pulse 0V. IC555 pin 4 is connected to the speaker probe +. Speaker probe - will be connected with C3 (capacitor 3) and grounded out, and the probe - the speakers will be connected with the source voltage -.
The working principle of the Bel 2 tone in which the DC voltage source is given in the IC555 serves as a timer tones, and used the switch that serves as a voter tone high (when the switch is turned ON) and low tone (when the switch position OFF).
Friday, September 5, 2014
Power Amplifier Circuit 2 x 20 W stereo with IC AN7156N
This circuit operate with IC AN7156N . You just can use this IC , because havnt similarity it. In this Circuit have 2 input IN R and IN L and have Output R and L . Voltage supply require 15 V , minimum voltage 9 V and maximum voltage 24V . And the voltage must DC voltage , and better the DC voltage filtering .
Maximum Output for 1 speaker 25 W , so this circuit have maximum output 2 X 25 W with minimum impedance 4 ohm. See this circuit schematic below :
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| Click image to view enlarge |
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