Showing posts with label electronic. Show all posts
Showing posts with label electronic. Show all posts
Wednesday, December 25, 2013
Best Electronic Crowbar Circuit Diagram for AC or DC lines
This is Best Electronic Crowbar Circuit Diagram for AC or DC lines. For positive protection of electrical or electronic equipment, use this against excessive supply voltage. Due to improper switching, wiring, short circuits, or failure of regulators, an electronic crowbar circuit can quickly place a short circuit across the power lines, thereby dropping the voltage across the protected device to near zero and blowing a fuse.
The triac and SBS are both bilateral devices, the circuit is equally useful on ac or dc supply lines. With the values shown for Rl, R2, and R3, the crowbar operating point can be adjusted over the range of 60 to 120 volts dc or 42 to 84 volts ac. The resistor values can be changed to cover a different range of supply voltages. The voltage rating of the triac must be greater than the highest operating point as set by R2, II is a low power incandescent lamp with a voltage rating equal to the supply voltage.
Best Electronic Crowbar Circuit Diagram for AC or DC lines
It may be used to check the set point and operation of the unit by opening the test switch and adjusting the input or set point to fire the SBS. An alarm unit such as the Mallory Sonalert may be connected across the fuse to provide an audible indication of crowbar action. (This circuit may not act on short, infrequent power line transients).
Wednesday, October 2, 2013
Electronic Ear for Lego RCX Module
One interface that is missing in the Lego MindStorms system is an electronic ear. We don’t mean that the RCX should respond to spoken commands (which requires a large amount of electronics and software), but it would be handy if it could respond to basic sounds (or sound levels). The circuit presented here allows the RCX to sense different sound levels. The sound is picked up by a crystal microphone, which is an inexpensive component that is available in every electronics shop. The signal from the microphone is converted into a variable quasi-resistance value. The RCX, in turn, can use this value to determine if a particular sound level has been exceeded. If the trigger threshold is set to the right level, the RCX will then react to a previously set sound level. The RCX input must be configured as a light sensor input for this function.
The operation of the circuit is simple. IC1, which is wired as a non-inverting amplifier, amplifies the microphone signal by a factor of 100. The output signal from the opamp is rectified by D1 and smoothed by C1. Resistor R2 allows the capacitor to discharge. The resulting DC voltage drives IC2, which acts as a buffer. The output of this opamp is connected to the sensor input of the RCX via a 1-kΩ resistor (R1). Just as with the analogue input adapter described elsewhere in this website, the RCX sees a variable resistance value at the sensor input, and it converts this into a measurement value between 0 and 100.
In the idle state, when no sound is sensed, the measurement value lies between 90 and 100. The louder the sensed sound, the lower the measurement value. You can use the light-sensor routine of the Lego software to set the responses to various sound levels. If you use a threshold value of around 85, then a level under 85 will be sensed as a sound signal, while a level above 85 will be sensed as silence. If you clap your hands near the sensor, the circuit will detect this. If you use these ‘observations’ to increment a counter, it is even possible to measure the number of sound pulses within a defined interval, and then to carry out some action based on the result.
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The operation of the circuit is simple. IC1, which is wired as a non-inverting amplifier, amplifies the microphone signal by a factor of 100. The output signal from the opamp is rectified by D1 and smoothed by C1. Resistor R2 allows the capacitor to discharge. The resulting DC voltage drives IC2, which acts as a buffer. The output of this opamp is connected to the sensor input of the RCX via a 1-kΩ resistor (R1). Just as with the analogue input adapter described elsewhere in this website, the RCX sees a variable resistance value at the sensor input, and it converts this into a measurement value between 0 and 100.In the idle state, when no sound is sensed, the measurement value lies between 90 and 100. The louder the sensed sound, the lower the measurement value. You can use the light-sensor routine of the Lego software to set the responses to various sound levels. If you use a threshold value of around 85, then a level under 85 will be sensed as a sound signal, while a level above 85 will be sensed as silence. If you clap your hands near the sensor, the circuit will detect this. If you use these ‘observations’ to increment a counter, it is even possible to measure the number of sound pulses within a defined interval, and then to carry out some action based on the result.
Friday, April 12, 2013
HANDY 0 12V DC POWER SUPPLY ELECTRONIC DIAGRAM
HANDY 0-12V DC POWER SUPPLY ELECTRONIC DIAGRAM
For heat protection, heat sink is needed for the BD679 transistor. It is because it will be over tempered when works more than 200mA.
FEATURES:
0v to 12 volt output:
- 700mA with M 2155
- 1.4amp with M 2156
- 1A with 16v AC 1.5 amp plug pack
Thursday, April 11, 2013
Electronic Touch Switch
Mechanical contacts have the disadvantage that they wear out. That is why it is practical to use an electronic ‘touch switch’ in some situations. With such a touch switch the resistance of the human skin is used for the switching action. The schematic shows the design of a circuit that senses the resistance of the skin and converts it into a useful switching signal. The touch switch contacts can be made from two small metal plates, rivets, nails, etcetera, which are placed close together on a non-conducting surface. In this circuit a comparator of the type LM393 has been used. In the idle state there is, via R1, a voltage equal to the power supply voltage on the non-inverting input of IC1a.
Because the inverting input of IC1a is set with R2 and D3 to D5 at the supply voltage minus 1.8 V, the open-collector output of IC1.a is, via R3, equal to the power supply voltage. This voltage is inverted by IC1.b. The voltage at the non-inverting input of IC1.b amounts to half the power supply voltage (through voltage divider R4 and R5) and is lower than the voltage on the inverting input.
Electronic Touch Switch Circuit diagram:
The output of IC1.b is therefore a ‘0’. If the two touch contacts are bridged with a finger, the voltage at the non-inverting input will become low enough to cause the comparator to toggle state. The moistness of the skin results in a resistance of 1 to 10 MR. If this circuit is used in the vicinity of equipment that’s connected to the mains, then it can be sufficient to touch only the upper contact to operate the switch, provided that the circuit has been earthed. The body then acts as an antenna which receives the 50 Hz (or 60 Hz) from the mains.
This is enough to toggle IC1.a at the same 50 Hz. C1/R3 prevent this 50 Hz from reaching the input of IC1b and provide a useable ‘pulse’ of about 10 s at the output of IC1.b. Note that a fly walking across the touch switch conducts enough to generate a switching signal. So do not operate important things with this circuit (such as the heating system or the garage door). Do not make the wires between the touch contacts and the circuit too long to prevent picking up interference. The power supply voltage for the circuit is not very critical. Any regulated DC voltage in the range from 6 to 20 V can be used.
Author: Heino Peters - Copyright: Elektor Electronics Magazine
Source : http://www.ecircuitslab.com/2011/06/electronic-touch-switch.html
Source : http://www.ecircuitslab.com/2011/06/electronic-touch-switch.html
Wednesday, April 10, 2013
BURGLAR ALARM USING IC TIMER 555 556 ELECTRONIC DIAGRAM
BURGLAR ALARM USING IC TIMER 555/556 ELECTRONIC DIAGRAM
circuit diagram of burglar alarm using IC timer 555/556 is functioned as an alarm to prevent thief entering your house. The alarm would produce loud sound when a thin wire connecting resistor R1 with IC pin no 4 is broken. Thin fiber is used as the wire. The thinner the wire, the more responsive the alarm. This circuit needs 5-15V power supply, buzzer is used as a speaker. Here is the circuit schematic :
Parts list :
- Resistor R1 : 10k
- Resistor R2 : 68k
- Resistor R3 : 1k
- Polar capacitor C1 : 1uF/15 B
- Capacitor C2-C3 : 0.01uF
- IC Timer : NE555
Tuesday, April 9, 2013
AUDIO SCHEMATIC AND ROUTING ELECTRONIC DIAGRAM
AUDIO SCHEMATIC AND ROUTING ELECTRONIC DIAGRAM
It shows the connection and wiring between each parts and component of audio system of the vehicle such as the alternator, ignition switch, antenna meter, tail, audio, front speaker, rear speaker, tweeter speaker, and many more.
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