Showing posts with label simple. Show all posts
Showing posts with label simple. Show all posts
Saturday, August 3, 2013
Simple Audio Clipper Circuit Diagram
Simple Audio Clipper Circuit Diagram for use with headphones, this circuit sets the audio clipping level via a 5-KOhmhm pot. This type of noise clipper works best for pulse-type noise of low duty cycle, such as ignition noise. Rl sets the bias on the diodes for the desired limiting level.
Simple Audio Clipper Circuit Diagram
Thursday, August 1, 2013
Simple Ni cad charger Circuit Diagram
Simple Ni-cad charger Circuit Diagram uses constant current LEDs to adjust charging current. It makes use of LEDs that pass a constant current of about 15 mA for an applied voltage range of 2-18 V. They can be paralleled to give any multiple of 15 mA and they light up when current is flowing.The circuit will charge a single cell at 15, 30 or 45 mA or cells in. series up to the rated supply voltage limit (about 14 V).
Simple Ni-cad charger Circuit Diagram
Tuesday, May 14, 2013
Simple Tone generator Circuit
This is simple tone generator circuit.You can use this one for your
alarm circuits,bugler alarms etc.Here I have used Common Ic NE 555.you
can use this for various things Try to make new thing.
Friday, April 12, 2013
Simple Electronic Quiz Switch
One of the common rounds in the quizzes is the buzzer round. We are describing here a simple electronic circuit that can be used in any test or quiz competition. In this circuit, only four persons can participate, and every participant is assigned a certain number. Whenever a switch is pressed, the circuit locks the remaining three entries. At the same time, an alarm sounds and the designated switch number is displayed on the seven segment LED display.When a player presses his switch, the corresponding output of IC1 goes high. Let us suppose, when switch S1 is pressed, D1 input of IC1 goes low and its corresponding output Q1 goes high. As a result, current passes through D5 to piezo buzzer PZ1, which creates a beep. At the same time, current also passes through diodes D6-D7 to show the number on the LED display.
Circuit diagram:
Simple Electronic Quiz Switch Circuit Diagram
Similarly, when any other switch (S2-S4) is pressed, the corresponding number gets displayed on seven segment displaying DIS1 and buzzer sounds. Switch S5 is used to reset the display exclusively. Switch S5 is a push to on switch. The circuit is powered by 9V battery. Assemble the circuit on a general purpose PCB and enclose it in a suitable case along with seven segment display and piezo buzzer. The assembled circuit can be kept near the host and the switches connected through the external can be assigned to the players.
http://streampowers.blogspot.com/2012/06/simple-electronic-quiz-switch.html
Thursday, April 11, 2013
Simple Analogue Electronic Key
This circuit uses two comparator that are combined in what is called a window comparator, i.e. resistors R2, R5, and R10 determine a voltage window within which the voltage applied to the junction of D2 and D6 must lie in order for the outputs of IC2.A and IC2.B to both be high at the same time. Given the value used for these resistors, this window is from 10/21 to 11/21 of the comparator supply rail (5 V). If IC2.A and IC2.B outputs are both high at the same time, transistor T1 is saturated via the AND gate formed by D3 and D4, and relay RE1 is energized to operate the electric latch or any other locking device.
Analogue Electronic Key Circuit Diagram
The key is defined by the generation of the specif ic voltage at the junction of D2 and D6, formed, for example, by a simple stereo jack containing the two resistors R4 and R8. Together with R1 and R9, they form a potential divider that needs to be suitably calculated in conjunction with the values of R2, R5, and R10 so that the key can open the lock. Clearly, all this will only work correctly is the supply voltage to these two dividers is stable, which is ensured by IC1, regulating it to 5 V.If we had set the values for R1 and R9, all the readers of this edition of Elektor would have had the same key, which is clearly not a good idea! So you need to decide for yourself not only R4 and R8, which form the key, but also R1 and R9 which let you customize the ‘lock’.1 Here are the relationships between the values of resistors R1, R4, R8, and R9 for the key to be able to open the lock:
10 · R8 · R9 < 11 · (R1 + R4) · (R8 + R9) 10 · (R1 + R4) · (R8 + R9) < 11 · R8 · R9
Given the size of the window for me d by R2, R5, and R10, 5 % tolerance resistors are adequate.
Note too that, as the relationships consist of inequalities, and that there are only two (un)equations for four unknowns, this leaves quite a wide choice for the resistor values. We advise you to set at least two of them to preferred values, which will then let you work out the others. If, as is more than likely, this does not result in other preferred values, you’ll then need to use series/parallel combinations to obtain the calculated values or else choose different starting values in order to arrive at a better compromise.
Wednesday, April 10, 2013
Simple Daul Regulator Handles Two Input Voltages
The circuit in Fig 1 supplies both 3.3 and 5V to transitional circuits that employ both the new 3.3V and older 5V devices. Additionally, because the regulator accepts either 3.3 or 5V inputs, you could plug it into either a new 3.3V system or an old 5V system.The circuit consists of two sections: a dc/dc converter and a double-pole, double-throw (dpdt) switch. The dpdt switch comprises a pair of dual n-channel MOSFETs (Q2 and Q3) and their associated high-side drivers.
Upon power-up, the comparator in IC2 determines the state of the circuit. The comparator’s output, IC2 pin 6, goes to the input of the MOSFET driver, IC1. The driver internally generates a gatedrive voltage 8.8V above the device’s supply voltage. This high voltage drives the appropriate MOSFETs in Q2 and Q3.
IC2 is also the heart of a flying-capacitor, buck/boost dc/dc converter. Unlike other switching-regulator schemes, this topology needs no transformers. Transistor Q1 controls this section’s output voltage, VS. When VIN is at 5V, Q1 is off, forcing the section to operate as a step-down converter. In this mode, the section produces 3.3V, which goes to the output through Q3B. Also in this mode, 5V power goes directly through Q2A, and Q2B and Q3A are both off.
Upon power-up, the comparator in IC2 determines the state of the circuit. The comparator’s output, IC2 pin 6, goes to the input of the MOSFET driver, IC1. The driver internally generates a gatedrive voltage 8.8V above the device’s supply voltage. This high voltage drives the appropriate MOSFETs in Q2 and Q3.
IC2 is also the heart of a flying-capacitor, buck/boost dc/dc converter. Unlike other switching-regulator schemes, this topology needs no transformers. Transistor Q1 controls this section’s output voltage, VS. When VIN is at 5V, Q1 is off, forcing the section to operate as a step-down converter. In this mode, the section produces 3.3V, which goes to the output through Q3B. Also in this mode, 5V power goes directly through Q2A, and Q2B and Q3A are both off.
When VIN is 3.3V, IC1 turns on Q1, shorting out the 140-kΩ resistor and forcing the dc/dc-converter section into step-up mode. In this mode the converter section generates 5V at VS, powering the 5V output via Q2B. Also in this mode, 3.3V goes directly from the circuit’s input to the output via Q3A. Q2A and Q3B are both off.No-load quiescent current consumption is approximately 500 μA.
Lower-frequency converters would reduce power consumption at the expense of a larger inductor. The efficiency of the dc/dc-converter section is 73% in either mode. But because this power accounts for only half of the circuit’s output power, the circuit’s overall efficiency is approximately 80% with VIN=3.3V and 86% with VIN=5V.
Lower-frequency converters would reduce power consumption at the expense of a larger inductor. The efficiency of the dc/dc-converter section is 73% in either mode. But because this power accounts for only half of the circuit’s output power, the circuit’s overall efficiency is approximately 80% with VIN=3.3V and 86% with VIN=5V.
Thursday, April 4, 2013
Simple Circuit Detects Voltage Over Ranges
Sometimes, a visual indication of whether a sensed voltage is above or below its nominal value can be useful. Most approaches to over voltage or under voltage sensing use two voltage comparators and a resistor divider to form a window comparator. The circuit in Figure 1a is an alternative to the traditional window-comparator approach. It provides different-color indications if the sensed voltage is above or below the preset value; in this case, it is centered around 0V.
The circuit uses a FET-input, low-offset-voltage OPA124 op amp and a dual-color LED. The forward voltages for the red and green LED sections are 2 and 2.1V, respectively. The values of the op-amp feedback resistors R1 and R2 are such that the op amps closed-loop gain, 1+R2/R1, equals VLED/VWIN, where VWIN is the desired positive or negative window threshold. Thus, whenever the input voltage, VIN, exceeds ±VWIN in magnitude, the op-amp stage supplies a voltage that turns on the corresponding LED. When VIN>+VWIN, the red LED turns on; when VIN<–VWIN, the green LED turns on. Whenever –VWIN
For input voltages greater than 0V, the op amp produces a negative voltage and Q1 turns off. The ratio of R2 and R1 sets the op-amp gain, and the output clamps at the on-state voltage of the green LED, approximately –2.1V. For input voltages lower than 0V, Q1 turns on once the op amps output exceeds the threshold voltage of Q1. In this case, the ratio of R1 and the parallel combination of R2 and R3 sets the op-amp gain, and the maximum output voltage is the on-state voltage of the red LED, 2V. Resistor R4 again serves as a current limiter for the LEDs. The relationship between the resistor values and the positive and negative window voltages is given by the following equations. For simplicity, we use only the positive magnitude of the voltages, and we neglect the difference between the forward voltages of the red and green LEDs.
Wednesday, April 3, 2013
Simple Infrared Remote Control Extender
This ultra-simple remote control extender is ideal for use with a hidden video recorder. The recorder is a Panasonic NV-SD200 and is used as part of a camera surveillance system. A PICAXE-08-based circuit is used to detect events and control the recorder. It also flashes a LED near the monitor to indicate the number of events since last viewing.
Click for larger image
Strangely, the NV-SD200 model refused to work with a number of commercial infrared remote control extenders, hence the need for this design. As a bonus, it uses less power than a traditional extender (no plugpacks) and the remote can still be used in the normal manner.
As shown, an additional 5mm infrared LED is mounted directly in front of the equipment to be controlled. This is cabled back to a convenient location near the monitor and terminated in a 3.5mm plug.
To modify the remote control unit, break the circuit to the anode of the existing infrared LED and wire in a 3.5mm headphone socket. In most cases, the LED will be accessible without dismantling the circuit board. The purpose of the socket is to allow the existing infrared LED to operate normally when the jack is unplugged.
If the socket won’t fit inside the case, then a very short flying lead with a moulded in-line socket can be used instead. By using light-duty figure-eight cable, the transmitting LED could be 30m or more from the hand-held remote control without problems.
[Continue reading]
Click for larger image
Strangely, the NV-SD200 model refused to work with a number of commercial infrared remote control extenders, hence the need for this design. As a bonus, it uses less power than a traditional extender (no plugpacks) and the remote can still be used in the normal manner.
As shown, an additional 5mm infrared LED is mounted directly in front of the equipment to be controlled. This is cabled back to a convenient location near the monitor and terminated in a 3.5mm plug.To modify the remote control unit, break the circuit to the anode of the existing infrared LED and wire in a 3.5mm headphone socket. In most cases, the LED will be accessible without dismantling the circuit board. The purpose of the socket is to allow the existing infrared LED to operate normally when the jack is unplugged.
If the socket won’t fit inside the case, then a very short flying lead with a moulded in-line socket can be used instead. By using light-duty figure-eight cable, the transmitting LED could be 30m or more from the hand-held remote control without problems.
Sunday, March 31, 2013
How to Make a Simple 12 Volt LED Lantern Circuit
We have discussed white LEDs comprehensively through many of my earlier articles and have learned how efficient these lights are with power consumption.
In this article we will study a very simple configuration for making a LED lamp or a LED lantern.
New electronic enthusiasts often get confused with the wiring intricacies while configuring many LEDs in groups.
Here we’ll see how we can connect as many as 64 LEDs for making the proposed unit.
The circuit diagram details may be understood from the following points:
White LEDs typically have a forward voltage drop of about 3 volts.
When operated at the above voltage level, the device is able to produce lights at optimum levels and the spec also maintains better life expectancy.
The minimum current required at the above voltage level is around 20 mA, which again is an optimal magnitude and is ideally suited for a white LED.
That means for driving a single white LED in the most straightforward way we would require 3 * 0.02 = 0.06 watts, that’s pretty negligible compared to the relative illumination received from it.
The best thing is that as long as the above voltage and current spec is observed, the device continues to consume 0.06 watts irrespective of the number of LEDs connected.
In the present circuit, the maximum voltage available is 12, dividing 12 by 3 = 4, meaning 4 numbers of LEDs can be accommodated at this voltage and yet we are able to limit the power to 0.06 watts.
However the above calculation would make the circuit quite vulnerable to voltage drops and if the voltage dropped even by a single volt would make the LED too dim or might just shut them OFF, we don’t want this to happen.
Therefore though the efficiency may drop a bit, we opt for a configuration which would enable the circuit to work even at lower voltages. We include only two LEDs in the series @ o.06 watts.
Now it’s all about connecting the desired number of strings of two LEDs each in parallel until all the 64 bulbs are included in the circuit.
However connecting in parallel would mean multiplying current. Since we have 32 parallel connections means the total consumption will now become 32 * 0.06 = 1.92 watts, still pretty much reasonable.
The connection details can be easily traced from the given schematic.
Your simple LED lantern is ready and may be taken anywhere outdoors with you, probably during night time explorations.
Pats List
All resistors are = 470 Ohms, 1.4 watts,
All LEDs are = white, 5mm, hi-efficiency
Diode = 1N4007
Thursday, March 28, 2013
Simple RF Detector For 2M
This simple circuit helps you sniff out RF radiation leaking from your transmitter, improper joints, a broken cable or equipment with poor RF shielding. The tester is designed for the 2-m amateur radio band (144-146 MHz in Europe). The instrument has a 4-step LED readout and an audible alarm for high radiation voltages. The RF signal is picked up by an antenna and made to resonate by C1-L1. After rectifying by diode D1, the signal is fed to a two-transistor high-gain Darlington amplifier, T2-T3.
Assuming that a 10-inch telescopic antenna is used, the RF level scale set up for the LEDs is as follows: When all LEDs light, the (optional) UM66 sound/melody generator chip (IC1) is also actuated and supplies an audible alarm. By changing the values of zener diodes D2, D4, D6 and D8, the step size and span of the instrument may be changed as required. For operation in other ham or PMR bands, simply change the resonant network C1-L1. As an example, a 5-watt handheld transceiver fitted with a half-wave telescopic antenna (G=3.5dBd), will produce an ERP (effective radiated power) of almost 10 watts and an e.m.f. of more than 8 volts close to your head.
Inductor L1 consists of 2.5 turns of 20SWG (approx. 1mm dia) enameled copper wire. The inside diameter is about 7mm and no core is used. The associated trimmer capacitor C1 is tuned for the highest number of LEDs to light at a relatively low fieldstrength put up by a 2-m transceiver transmitting at 145 MHz. The tester is powered by a 9-V battery and draws about 15mA when all LEDs are on. It should be enclosed in a metal case.
[Continue reading]
Assuming that a 10-inch telescopic antenna is used, the RF level scale set up for the LEDs is as follows: When all LEDs light, the (optional) UM66 sound/melody generator chip (IC1) is also actuated and supplies an audible alarm. By changing the values of zener diodes D2, D4, D6 and D8, the step size and span of the instrument may be changed as required. For operation in other ham or PMR bands, simply change the resonant network C1-L1. As an example, a 5-watt handheld transceiver fitted with a half-wave telescopic antenna (G=3.5dBd), will produce an ERP (effective radiated power) of almost 10 watts and an e.m.f. of more than 8 volts close to your head.
Inductor L1 consists of 2.5 turns of 20SWG (approx. 1mm dia) enameled copper wire. The inside diameter is about 7mm and no core is used. The associated trimmer capacitor C1 is tuned for the highest number of LEDs to light at a relatively low fieldstrength put up by a 2-m transceiver transmitting at 145 MHz. The tester is powered by a 9-V battery and draws about 15mA when all LEDs are on. It should be enclosed in a metal case.Tuesday, March 26, 2013
Simple 5V Power Supply Digital Circuit
This circuit is a small +5V power supply, which is useful when experimenting with digital electronics. Small inexpensive wall tranformers with variable output voltage are available from any electronics shop and supermarket. Those transformers are easily available, but usually their voltage regulation is very poor, which makes then not very usable for digital circuit experimenter unless a better regulation can be achieved in some way. The following circuit is the answer to the problem.
This circuit can give +5V output at about 150 mA current, but it can be increased to 1 A when good cooling is added to 7805 regulator chip. The circuit has over overload and therminal protection.
Circuit diagram:
power supply Circuit diagram
The capacitors must have enough high voltage rating to safely handle the input voltage feed to circuit. The circuit is very easy to build for example into a piece of veroboard.
Pinout of the 7805 regulator IC
- 1. Unregulated voltage in
- 2. Ground
- 3. Regulated voltage out
Component list
7805 regulator IC
100 uF electrolytic capacitor, at least 25V voltage rating
10 uF electrolytic capacitor, at least 6V voltage rating
100 nF ceramic or polyester capacitor
Summary of circuit features
- Brief description of operation: Gives out well regulated +5V output, output current capability of 100 mA
- Circuit protection: Built-in overheating protection shuts down output when regulator IC gets too hot
- Circuit complexity: Very simple and easy to build
- Circuit performance: Very stable +5V output voltage, reliable operation
- Availability of components: Easy to get, uses only very common basic components
- Design testing: Based on datasheet example circuit, I have used this circuit succesfully as part of many electronics projects
- Applications: Part of electronics devices, small laboratory power supply
- Power supply voltage: Unreglated DC 8-18V power supply
- Power supply current: Needed output current + 5 mA
- Component costs: Few dollars for the electronics components + the input transformer cost
Modification ideas
More output current
If you need more than 150 mA of output current, you can update the output current up to 1A doing the following modifications:
Change the transformer from where you take the power to the circuit to a model which can give as much current as you need from output
Put a heatsink to the 7805 regulator (so big that it does not overheat because of the extra losses in the regulator)
Other output voltages
If you need other voltages than +5V, you can modify the circuit by replacing the 7805 chips with another regulator with different output voltage from regulator 78xx chip family. The last numbers in the the chip code tells the output voltage. Remember that the input voltage muts be at least 3V greater than regulator output voltage ot otherwise the regulator does not work well.
source :tkk
Monday, March 25, 2013
A Simple Fog Lamp Sensor
For several years now, a rear fog lamp has been mandatory for trailers and caravans in order to improve visibility under foggy conditions. When this fog lamp is switched on, the fog lamp of the pulling vehicle must be switched of to avoid irritating reflections. For this purpose, a mechanical switch is now built into the 13-way female connector in order to switch of the fog lamp of the pulling vehicle and switch on the fog lamp of the trailer or caravan. For anyone who uses a 7-way connector, this switching can also be implemented electronically with the aid of the circuit illustrated here.
Circuit diagram:
Fog Lamp Sensor Circuit Diagram
Here a type P521 optocoupler detects whether the fog lamp of the caravan or trailer is connected. If the fog lamp is switched on in the car, a current flows through the caravan fog lamp via diodes D1 and D2. This causes the LED in the optocoupler to light up, with the result that the photo-transistor conducts and energies the relay via transistor T1. The relay switches of the fog lamp of the car. For anyone who’s not all thumbs, this small circuit can easily be built on a small piece of perforated circuit board and then fitted somewhere close to the rear lamp fitting of the pulling vehicle.
Author :Harrie Dogge Copyright :Elektor Electronics 2008
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