Schematic Diagram: touch

Showing posts with label touch. Show all posts

Thursday, September 25, 2014

Simple Touch Operated Switch Circuit Diagram Using IC 555

The touch operated switch circuit basically comprises a touch activated mono- stable vibrator using an NE555 IC, which activates the TFL 7493 IC used as a bistable.

Transistor T2 is used to provide sufficient drive capability to drive the relay.
The power supply shown provides an appropriate DC voltage to drive a conventional relay. In the circuit, some special precautions have been taken to avoid interference pick-up, to which I`l`L ICs are especially prone. Capacitor C2 is rather large compared to the conventional value (0.01].tF) used in this position.
The extremal load is connected across the relay contacts.
This modification has proved quite effective. Another modification is the addition of Cl-RI parallel combination. The value of Rl is best chosen by trail and error, and is a compromise between sensitivity and immunity from stray pick·up, Its value lies in the range 1.8M to 1OM. R1 may be excluded altogether. An additional decoupling capacitor (0.01uF) may be added as close as possible to the supply terminals of IC 7493.
An LED with a suitable series resistance may be included in the circuit and placed in the center of the touch plate to indicate when the relay is activated. In cases of severe stray pick-up, the unit should be enclosed in a metal casing that should be grounded.
The prototype was constructed on a conventional bread board. To minimize stray pick-up, the interconnections should be as short as possible. If the unit is situated away from the touch sensor, a shielded wire should be used for the connection.
This causes a time delay before the load is actually activated. To avoid this, TI is introduced.
TI acts as an inverter and converts a rising edge into a falling edge.
The monostable is touch activated and it provides the triggering input to the bistable. However, the bistable triggers only on the falling edge of the monostable output pulse.

Tuesday, August 26, 2014

Simple Touch Switch

This is a simple touch schema diagram.I think you can use this for many purposes.I have used this schema as a security schema device.Here I have used very common Transistors 2N 5458 N and 2N2222 to gain the signal .2N3906 Transistor work as a switch here.

Note
# Build this schema on a PCB
# Use a copper plate to touch senseer
# Dont supply more than12V

Monday, August 18, 2014

Touch Switch II

This schema uses a 555 timer as the bases of the touch switch. You can learn more about 555 timers in the Learning section on my site. When the plate is touched the 555 timer is triggered and the output on pin 3 goes high turning on the LED and the buzzer for a certain period of time. The time that the LED and the buzzer is on is based on the values of the capacitor and resistor connected to pin 6 & 7. The 10M resistor on pin 2 causes the the schema to be very sensitive to the touch.

Streampowers

Sunday, August 10, 2014

Simple Touch Sensitive Switch Wiring diagram Schematic

This is a Simple Touch Sensitive Switch Circuit Diagram. A touch switch is a type of switch that only has to be touched by an object to operate. It is used in many lamps and wall switches that have a metal exterior as well as on public computer terminals.

Touch Sensitive Switch Circuit Diagram

A high impedance input is provided by Ql, a general purpose field effect transistor 741 op amp is used as a sensitive voltage level switch which in turn operates the current Q2, a medium current PNP bipolar transistor, thereby energizing the relay which can be used to control equipment, alarms, etc.