Friday, December 27, 2013

IR Remote Control Tester

Here’s a simple, low cost, and easy to construct infrared remote control tester. The tester is built around an easily available infrared receiver module (TSOP 1238).

 IR Remote Control Tester Circuit diagram:

Schematic diagram of IR remote control tester
Normally, data output pin 3 of the IR receiver module is at a high level (5 volts)and as such driver transistor T1 is in cut-off state. Whenever the IR receiver module receives a valid (modulated) infrared signal, its data output pin goes low in synchronism with the received infrared bursts. As a result, transistor T1 conducts during negative pulse period and the.LED blinks to indicate reception of signals from the remote such as TV remote control. A miniature active buzzer is connected at the collector of transistor T1 for audio indication.

Proposed enclosure with front-panel

The 5V DC for energizing the circuit is directly derived from the 230V AC mains supply. Unlike the conventional resistive voltage divider, a capacitive potential divider is used here, which does not radiate any heat and makes the tester quite compact. Another advantage of this tester is no false triggering due to the ambient light or electronic ballast-operated tubelights. A suggested enclosure for the circuit is shown in Fig. 2.
Source :

Thursday, December 26, 2013

Touch Sensitive Light Dimmer

With IC SLB0586A from Siemens you can build a simple touch light dimmer circuit that will allow you to adjust the lamp intensity. Together with a TIC206D triac, it enables smooth regulation of light intensity from a bulb of 10W – 400W. A coil of 100µH/5A is required to suppress switching noise.

The voltage supply is obtained through R2, C2, D1 and C3 and is about 5.3V below the network potential. The touch sensor that is used to drive the IC is connected at pin 5 through two 4.7MΩ resistors, R5 and R6, in order to ensure user security.

In the adjustable touch lamp schematic we can see three selection connection , for selecting one of three modes of the IC. When the B connection is used, the light will always be ON at the last level that we used. With A or C connection the light will be ON at the minimum intensity. With B or C, the purpose of regulation is reversed with each use.

Schematic of the adjustable light with touch sensor
Circuit Project: Touch light dimmer circuit
Touch Sensitive Light Dimmer Circuit Diagram

When the sensor is touched for a short period of time (50 – 400 ms), the lamp will be ON or OFF. If the sensor is touched for a longer period of time it will start the regulation process. Warning! This touch light dimmer circuit has some points where lethal 220V is present, please do not try this project if you are not qualified.

Wednesday, December 25, 2013

Simple Infra red Receiver

This very simple infra-red receiver is intended to form an infra-red remote control system with the simple infra-red transmitter described in this site. The system does not use any kind of coding or decoding, but the carrier of the transmitter is modified in a simple manner to provide a constant switching signal. Since the receive module, IC1, switches from low to high (in the quiescent state, the output is high) when the carrier is received for more than 200 milliseconds, the carrier is transmitted in the form of short pulse trains. This results in a pulse at the output of the receiver that has a duty cycle which is just larger than 12.5%. The carrier frequency used in the system is 36 kHz, so that the output frequency of IC1 is 281.25 Hz.

Infra-red Receiver Circuit diagram :

This signal is rectified with a time constant that is long enough to ensure good smoothing, so that darlington T1 is open for as long as the received signal lasts. A drawback of this simple system is that it may pick up signals transmitted by another infra-red (RC5) controller. In this case, only the envelopes of the pulse trains would appear at the output of T1. This effect may, of course, be used intentionally. For instance, the receiver may be used to drive an SLB0587 dimmer. Practice has shown that the setting of the SLB0587 is not affected by the RC5 pulses. The receiver draws a current of about 0.5 mA.

Source :

Tuesday, December 24, 2013

Super Universal Battery Charger Circuit Diagram

The Super Universal Battery Charger Circuit Diagram output voltage is adjustable and regulated, and has an adjustable constant-current charging circuit that makes it easy to use with most NiCad batteries. The charger can charge a single cell or a number of series-conoected cells up to a maximum of 18 V. 

Power transistors Ql and Q2 are conoected as series regulators to control the battery charger`s output voltage and charge-current rate. An LM317 adjustable voltage regulator supplies the drive signal to the bases of power transistors Ql and Q2. Potentiometer R9 sets the output-voltage level. A current-sampling resistor, R8 (a 0.1-!J, 5-W unit), is conoected between the negative output lead and circuit ground. For each amp of charging that flows through R8, a 100 mV output is developed across it. 

The voltage developed across RS is fed to one input of comparator U3. The other input of the comparator is connected to variable resistor RIO. As the charging voltage across the battery begins to drop, the current through RS decreases. Then the voltage feeding pin 5 of U3 decreases, and the comparator output follows, turning Q3 back off, which completes the signal`s circular path to regulate the battery`s charging current. The charging current can be set by adjusting RlO for the desired current. The circuit`s output voltage is set by R9. 

Super Universal Battery Charger Circuit Diagram

Super Universal Battery Charger Circuit Diagram


Monday, December 23, 2013

12V Touch Switch Exciter

This circuit is designed to generate a 20KHz pseudo sine wave signal that can power about 50 remote touch activated switch circuits.  It can support a cable length of about 2500 feet.  A typical remote switch circuit is also shown as well as a receiver circuit for those switches.

Source: DiscoverCircuits

Sunday, December 22, 2013

Simple Video Amplifier

The video amplifier in the diagram is a well-known design. Simple, yet very useful, were it not for the ease with which the transistors can be damaged if the potentiometers (black level and signal amplitude) are in their extreme position. Fortunately, this can be obviated by the addition of two resistors.

Circuit diagram :

Simple Video Amplifier-Circuit Diagram Simple Video Amplifier Circuit Diagram


If in the diagram R 3 and R 4 were direct connections, as in the original design, and P 1 were fully clockwise and P 2 fully anticlockwise, such a large base current would flow through T 1 that this transistor would give up the ghost. Moreover, with the wiper of P 2 at earth level, the base current of T 2 would be dangerously high. Resistors R 3 and R 4 are sufficient protection against such mishaps, since they limit the base currents to a level of not more than 5 mA.

Shunt capacitor C 4 prevents R 4 having an adverse effect on the amplification.


Saturday, December 21, 2013

Build a Inexpensive Isolation Transformer Circuit Diagram

Build a Inexpensive Isolation Transformer Impromptus Setup Circuit Diagram. Using two 12-V filament or power transformers, an impromptu isolation transformer can be made for low-power (under 50 W) use in testing or servicing. SOI is an ordinary, duplex ac recept-able. Use heavy-wire connections between the 12-V windings because several amperes can flow.

Inexpensive Isolation Transformer Circuit Diagram

Inexpensive Isolation Transformer Circuit Diagram


Friday, December 20, 2013

AC 220V Mains Powered Emergency Light and Alarm

This circuit is permanently plugged into a mains socket and NI-CD batteries are trickle-charged. When a power outage occurs, the lamp automatically illuminates. Instead of illuminating a lamp, an alarm sounder can be chosen. When power supply is restored, the lamp or the alarm is switched-off. A switch provides a "latch-up" function, in order to extend lamp or alarm operation even when power is restored.

Emergency Light and Alarm Circuit Diagram
Emergency Light and Alarm Circuit Diagram

Parts List:

R1 = 220K
R2 = 470R
R3 = 390R
R4 = 1.5K
R5 = 1R
R6 = 10K
R7 = 330K
R8 = 470R
R9 = 100R
D1 = 1N4007
D2 = 1N4007
D3 = 1N4007
D4 = 1N4007
D5 = 1N4007
D6 = Led
D7 = 1N4148
Q1 = BC547
Q2 = BC327
Q3 = BC547
Q4 = BC547
Q5 = BC327
C1 = 330nF-400V
C2 = 10uF-63V
C3 = 100nF-63V
C4 = 10nF-63V
LP1 = 2.5V-300mA Torch Lamp Bulb
PL1 = Male Mains Plug
SW1 = SPST Switches
SW2 = SPST Switches
SW3 = SPDT Switches
SPKR = 8 Ohms Loudspeaker
B1 = 2.5V Battery (two AA NI-CD rechargeable cells wired in series)

Mains voltage is reduced to about 12V DC at C2s terminals, by means of the reactance of C1 and the diode bridge (D1-D4). This avoids the use of a mains transformer. Trickle-charging current for the battery B1 is provided by the series resistor R3, D5 and the green LED D6 that also monitors the presence of mains supply and correct battery charging.

Q2 & Q3 form a self-latching pair that start operating when a power outage occurs. In this case, Q1 biasing becomes positive, so this transistor turns on the self latching pair. If SW3 is set as shown in the circuit diagram, the lamp illuminates via SW2, which is normally closed; if set the other way, a square wave audio frequency generator formed by Q4, Q5 and related components is activated, driving the loudspeaker.

If SW1 is left open, when mains supply is restored the lamp or the alarm continue to operate. They can be disabled by opening the main on-off switch SW2. If SW1 is closed, restoration of the mains supply terminates lamp or alarm operation, by applying a positive bias to the Base of Q2.


Close SW2 after the circuit is plugged.


The circuit is connected to 230Vac mains, then some parts in the circuit board are subjected to lethal potential!. Avoid touching the circuit when plugged and enclose it in a plastic box.


Thursday, December 19, 2013

Solar Power Supply

This circuit delivers either 4.8 or 7.2 V regulated at 15 mA with a 3-V input from a bank of photocells. Rl should be 453 kQ for a 7.2-V output and 274 РЁ for a 4.8-Vdc output. Regulator efficiency is around 70%. This should be considered when selecting suitable solar cells.

Solar Power Supply Circuit diagram :


Wednesday, December 18, 2013

The ordering quantity of this order of Cell Phone Jammers is large enough

The document of  Cell Phone Jammers  will contain the important product information of  Cell Phone Jammers  .
The laser has been widely applied to the laser welding, laser cutting, laser drilling (including the slant-hole, different holes, plaster hole, perforated tipping paper, perforated steel, perforated packaging and printing, etc.), laser hardening, laser heat treatment, laser marking, glass engraving, laser trimming, laser lithography, laser system, film, laser film processing, laser packages, laser repair circuits, laser routing technology, laser cleaning.
Periodic illegible: often drum charge roller coating or contamination, watermarks, mimeo, fingerprints often cause this defect. Grapes: It is the same as the overlapping coins appear in the printed materials of a defect, no rules, and difficult to repeat, is caused by bad drum ground. Background scattering: refers to the text or unwanted lines around the black specks, toner from the magnetic roller coating or bad cause. Drum overheating (referring to a sense of high) may also cause this defect. Wave background (tiger grouper): wavy black version in white or white on black version or in the form of half-tone version. Several more kinds of payment method of  Cell Phone Jammers  will be added for this online store of  Cell Phone Jammers  .
Usually magnetic roller sleeve coating defects or due to prolonged low-density printing, magnetic bond caused by the magnetic roller sleeve. Hollow words: refers to the text or images is missing strokes on the reasons: toner itself is the problem. Dark pink with bad. Magnetic roller coating problems. Print media over the surface of the light, perfect. Paper with the negative. Irregular vertical black spots: the deformation caused by the sealing of the waste toner smears scattered. As the accumulation of too much toner on the magnetic roller, causing leakage of powder. Coloration: with a variety of factors: the toner itself is the problem. Toner, magnetic roller with the problem. Flour knife aging. Magnetic roller wear. Drums to life. High humidity or moisture absorption media. The detailed information of  Cell Phone Jammers  contains the ordering quantity of  Cell Phone Jammers  .
Bottom ash: bottom ash refers to prints blank zone in the mist toner, but also with a variety of factors: aging scraper. Charge roller fouling. Toner problem. Drum fatigue, to life. Low temperature and dry environment. Print media bad. Charge roller wear. Fixing is not strong: refers to the printed text or images on the product that is out of touch. The reasons are: toner softening point higher than the machines fusing temperature. Print media too thick or too light surface. Before cleaning the printer, be sure to carefully read the printer user manual to follow any special procedures and warnings. The ordering quantity of this order of  Cell Phone Jammers  is large enough.

Tuesday, December 17, 2013

DC Fan Controller

This circuit is ideal to control the cooling fan of heat generated electronic gadgets like power amplifiers. The circuit switches on a fan if it senses a temperature above the set level. The fan automatically turns off when the temperature returns to normal. The circuit uses an NTC (Negative Temperature Coefficient) Thermister to sense heat. NTC Thermister reduces its resistance when the temperature in its vicinity increases.

IC1 is used as a voltage comparator with two potential dividers in its inputs. Resistor R1 and VR1 forms one potential divider connected to the non inverting input of IC1 and another potential divider comprising R2 and the 4.7K Thermistor supplying a variable voltage to the inverting input of IC1. VR1 is adjusted so as to give slightly lesser voltage at the non inverting input than the inverting input at room temperature.

DC Fan Controller Circuit

In this state, output of IC1 will be low and the Fan remains off. When the temperature near the Thermister increases, its resistance decreases and conducts. This drops the voltage at pin 2 of IC1 and its output becomes high. T1 then triggers and fan turn on. Red LED indicates that fan is running. Capacitor C1 gives a short lag before T1 turns on to avoid false triggering and to give proper bias to T1.

DC fan can be the one used in Computer SMPS. Keep the Thermistor near the heat sink of the Amplifier PCB and switch on the amplifier for 10 minutes. Then adjust VR1 till the Fan stop running.When the temperature rises, Fan will automatically switch on.