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ON-OFF Touch Switch Circuit เผื่อใครจะเอาไปใช้ ปิด-เปิด เครื่องdacหรือแอมป์หูฟัง
IC1 : 555 timer IC
Q1 : BC547
D1 : 1N4148
D2 : Red LED 3 or 5 mm.
R1, R2 : 3.3M
R3 : 10K
R4 : 1K
C1 : 10nF 63V
JF1, JF2 : Metal Plate
RL1 : 12V Relay
This is the On-Off touch switch circuit project. Modern mechanical switches are improved compared with those old technology. But sometimes we need to replace an old switch, or to control the electric current which is higher than the strength of switch to deliver a supply, or you need a switch that has more contemporary appearance. For these and other purposes, it is the essential the above circuit.
This circuit is simple and easy in construction and componentss which are required to build this circuit can be found at every electronic parts store. It is based on the famous 555, which drives a relay whose contacts play the role of the switch. These metal surfaces can have a form that we want, but must be clean and close the circuit. You just need to touch one of the two metal surfaces to change the condition of the switch/contacts of RL1. The surface JF1 is used to close the contacts of RL1 [ON] or surface JF2 is used to open the contacts of RL1 [OFF]. The current will be controlled by RL1 is dependent on contacts. The Led D2 will be turned on when switch is in ON position and the contacts of RL1 closed.
---------------------------------------------------------
Soft-Start and Pulse Transformer Power Supply
When you switch power supply amplifiers, laboratory and other PS in the network there is interference caused by triggering currents of transformers, charge currents of electrolytic capacitors and the start of powered devices themselves. Outwardly, this interference manifests itself as a "blinking" light pops and sparks to an electrical outlet and electrically ? this drawdown line voltage, which can lead to failure and instability of other devices that are powered from the same network.
In addition, these inrush currents cause burning of contacts of switches, power outlets. Another negative impact of inrush current ? rectifier diodes at the start of this work by the current overload and could be damaged. For example, the inrush current charging the capacitor 10,000uF 50V can reach more than 10 amps. If the diode bridge is not designed for this current operating environment may bring the bridge down. Especially strong inrush currents seen at a power 50-100W. For these power units offer the starter.
When you enable the network adapter current limiting resistor starts through R4. After some time needed for its start, capacitor charging and starting load resistor shunted by relay contacts and the power supply output to full capacity. Closing time is determined by the capacitance of the capacitor C2. C1, D1, C2, D2 elements are transformerless power supply for control circuit relay. Zener diode D2 plays a purely defensive role, and an intact control scheme may be missing. Relay BS-115C-12V, was used in the scheme may be replaced by any other relay contacts with a current of at least 10A, with the selection of diodes, a capacitor C1 and the choice of transistor VT1 on voltages, high voltage relay. Zener diode D3 provides hysteresis between the voltage on and off switch. In other words, the relay will turn sharply, but not smoothly.
The capacitor C1 determines the current of the relay. In case of insufficient current capacity of the condenser must be increased (0.47-1uF 400-630V). In protective wrap for the capacitor is desirable to put on tape or shrink it up. Fuses are selected on the two-times the rated current of power supply. For example, for a 100W power supply fuses must be current on 2 * (100/220) = 1A. If necessary, the scheme can be complemented by a network balanced / unbalanced filter on after the fuses. Connection with the case, which is present in the scheme can be regarded only as a common wire to connect the tester. In no case can it connect to the chassis device, display it on the general wire-line filters, etc.
---------------------------------------------------------
Low Voltage regulators with short circuit protection
These Low Voltage regulators with short circuit protection can provide 6, 7.5, and 9 V from an automobile battery supply of 13.5 V nominal, however, they will function just as well if connected to a smoothed dc output from a transformer/rectifier circuit.
Two types are shown for both positive and negative ground systems. The power transistors can be mounted on the heatsink without a mica insulating spacer thus allowing for greater cooling efficiency. Both circuits are protected against overload or short-circuits. The current can?t exceed 330 mA. Under normal operating conditions the voltage across R2 does not rise above the 500 mV necessary to turn Q2 on and the circuit behaves as if there was only Q1 present. If excessive current is drawn, Q2 turns on and cuts off Q1, protecting the reg-ulating transistor. The table gives the values of R1 for different zener voltages.
---------------------------------------------------------
Dual Polarity Power Supply +/- 15V based Transistors
This Dual supply circuit is suitable for installation of power analog (audio or measurement), it provides a bipolar voltage with voltage source between 20 and 50 V (in audio power amp, for example). Regulated output voltage is 15V, but can be adjusted from + /-12V or + /-18V by simply changing two components. The maximum output current must not exceed 100 mA each branch.
If you ask, where the transformer and diode rectifier?
This circuit is intended to be transplanted into an existing circuit (eg audio amp), which already provides symmetric voltage between + /-20V and + /-50V.
Reduction and voltage regulation
The settings output voltage is provided by two zener diodes D1 to D2 for positive and negative branches. The polarization of the two diodes are provided respectively by R1 and R2. ?Power? of the series was entrusted to two transistors BD139 and BD140, which should also be provided with a heatsink to ensure proper cooling. It may seem strange when should put some of the heatsink for low power output (max 100 mA). But the reality is that both transistors will be able to dissipate high power in this case max current .
The output voltages are not equal to 15V!
If you measure + / -14.5 V output instead of + /-15V, do not worry, it?s normal. Voltages + /-15V are determined by the zener diodes, which are likely to have a voltage different from one model to another (the dispersion characteristics are quite large). Moreover, the two transistors are connected in voltage follower, meaning found on the emitter, the voltage applied to the base, unless the fall of base-emitter voltage is in the range of 0, 6V. In practice, you should find out, a voltage can be between 14 V and 15.5 V. Outside this range, you can consider that there is a problem and you should check the wiring and the condition of the components.
Modification of the output voltage
Just replace the zeners D1 and D2. The value of 12V is limited, if you go under, the voltage drop across the transistors will continue to rise and they will heat up more. The value of 18V or 24V, however, is more acceptable, but be careful if the supply circuit contains op amp, the maximum voltage generally accepted for these is + /-18V! You may need to decrease slightly the value of resistors R1 and R2 if the zeners are 24V and the input voltage is ?only? 30V.
ON-OFF Touch Switch Circuit เผื่อใครจะเอาไปใช้ ปิด-เปิด เครื่องdacหรือแอมป์หูฟัง
IC1 : 555 timer IC
Q1 : BC547
D1 : 1N4148
D2 : Red LED 3 or 5 mm.
R1, R2 : 3.3M
R3 : 10K
R4 : 1K
C1 : 10nF 63V
JF1, JF2 : Metal Plate
RL1 : 12V Relay
This is the On-Off touch switch circuit project. Modern mechanical switches are improved compared with those old technology. But sometimes we need to replace an old switch, or to control the electric current which is higher than the strength of switch to deliver a supply, or you need a switch that has more contemporary appearance. For these and other purposes, it is the essential the above circuit.
This circuit is simple and easy in construction and componentss which are required to build this circuit can be found at every electronic parts store. It is based on the famous 555, which drives a relay whose contacts play the role of the switch. These metal surfaces can have a form that we want, but must be clean and close the circuit. You just need to touch one of the two metal surfaces to change the condition of the switch/contacts of RL1. The surface JF1 is used to close the contacts of RL1 [ON] or surface JF2 is used to open the contacts of RL1 [OFF]. The current will be controlled by RL1 is dependent on contacts. The Led D2 will be turned on when switch is in ON position and the contacts of RL1 closed.
---------------------------------------------------------
Soft-Start and Pulse Transformer Power Supply
When you switch power supply amplifiers, laboratory and other PS in the network there is interference caused by triggering currents of transformers, charge currents of electrolytic capacitors and the start of powered devices themselves. Outwardly, this interference manifests itself as a "blinking" light pops and sparks to an electrical outlet and electrically ? this drawdown line voltage, which can lead to failure and instability of other devices that are powered from the same network.
In addition, these inrush currents cause burning of contacts of switches, power outlets. Another negative impact of inrush current ? rectifier diodes at the start of this work by the current overload and could be damaged. For example, the inrush current charging the capacitor 10,000uF 50V can reach more than 10 amps. If the diode bridge is not designed for this current operating environment may bring the bridge down. Especially strong inrush currents seen at a power 50-100W. For these power units offer the starter.
When you enable the network adapter current limiting resistor starts through R4. After some time needed for its start, capacitor charging and starting load resistor shunted by relay contacts and the power supply output to full capacity. Closing time is determined by the capacitance of the capacitor C2. C1, D1, C2, D2 elements are transformerless power supply for control circuit relay. Zener diode D2 plays a purely defensive role, and an intact control scheme may be missing. Relay BS-115C-12V, was used in the scheme may be replaced by any other relay contacts with a current of at least 10A, with the selection of diodes, a capacitor C1 and the choice of transistor VT1 on voltages, high voltage relay. Zener diode D3 provides hysteresis between the voltage on and off switch. In other words, the relay will turn sharply, but not smoothly.
The capacitor C1 determines the current of the relay. In case of insufficient current capacity of the condenser must be increased (0.47-1uF 400-630V). In protective wrap for the capacitor is desirable to put on tape or shrink it up. Fuses are selected on the two-times the rated current of power supply. For example, for a 100W power supply fuses must be current on 2 * (100/220) = 1A. If necessary, the scheme can be complemented by a network balanced / unbalanced filter on after the fuses. Connection with the case, which is present in the scheme can be regarded only as a common wire to connect the tester. In no case can it connect to the chassis device, display it on the general wire-line filters, etc.
---------------------------------------------------------
Low Voltage regulators with short circuit protection
These Low Voltage regulators with short circuit protection can provide 6, 7.5, and 9 V from an automobile battery supply of 13.5 V nominal, however, they will function just as well if connected to a smoothed dc output from a transformer/rectifier circuit.
Two types are shown for both positive and negative ground systems. The power transistors can be mounted on the heatsink without a mica insulating spacer thus allowing for greater cooling efficiency. Both circuits are protected against overload or short-circuits. The current can?t exceed 330 mA. Under normal operating conditions the voltage across R2 does not rise above the 500 mV necessary to turn Q2 on and the circuit behaves as if there was only Q1 present. If excessive current is drawn, Q2 turns on and cuts off Q1, protecting the reg-ulating transistor. The table gives the values of R1 for different zener voltages.
---------------------------------------------------------
Dual Polarity Power Supply +/- 15V based Transistors
This Dual supply circuit is suitable for installation of power analog (audio or measurement), it provides a bipolar voltage with voltage source between 20 and 50 V (in audio power amp, for example). Regulated output voltage is 15V, but can be adjusted from + /-12V or + /-18V by simply changing two components. The maximum output current must not exceed 100 mA each branch.
If you ask, where the transformer and diode rectifier?
This circuit is intended to be transplanted into an existing circuit (eg audio amp), which already provides symmetric voltage between + /-20V and + /-50V.
Reduction and voltage regulation
The settings output voltage is provided by two zener diodes D1 to D2 for positive and negative branches. The polarization of the two diodes are provided respectively by R1 and R2. ?Power? of the series was entrusted to two transistors BD139 and BD140, which should also be provided with a heatsink to ensure proper cooling. It may seem strange when should put some of the heatsink for low power output (max 100 mA). But the reality is that both transistors will be able to dissipate high power in this case max current .
The output voltages are not equal to 15V!
If you measure + / -14.5 V output instead of + /-15V, do not worry, it?s normal. Voltages + /-15V are determined by the zener diodes, which are likely to have a voltage different from one model to another (the dispersion characteristics are quite large). Moreover, the two transistors are connected in voltage follower, meaning found on the emitter, the voltage applied to the base, unless the fall of base-emitter voltage is in the range of 0, 6V. In practice, you should find out, a voltage can be between 14 V and 15.5 V. Outside this range, you can consider that there is a problem and you should check the wiring and the condition of the components.
Modification of the output voltage
Just replace the zeners D1 and D2. The value of 12V is limited, if you go under, the voltage drop across the transistors will continue to rise and they will heat up more. The value of 18V or 24V, however, is more acceptable, but be careful if the supply circuit contains op amp, the maximum voltage generally accepted for these is + /-18V! You may need to decrease slightly the value of resistors R1 and R2 if the zeners are 24V and the input voltage is ?only? 30V.
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