How the Circuit Works. In the circuit, pin 2 and pin 6 are connected, and pins 4 and 8 are also connected. Mouser offers inventory, pricing, & datasheets for latching switch. The above latching switch uses an SCR as the latch. Releasing the switch, S1, has no effect on turning off the buzzer. single push button ON OFF relay latching switch one push button start stop relay. The latch circuit can be handy in an alarm circuit. It is a volatile memory, therefore the data vanishes when power failure occurs. Switch ICs are available at Mouser Electronics. latching switch are available at Mouser Electronics. We can use a soft latch circuit to auto-turn off ESP32, ESP8266, Arduino, or any other microcontrollers. Latching Toggle switches are one of the most popular kinds of switches, from their use by kids in basic electricity classes to their use in prototypes and more advanced products, they provide a familiar and reliable way to close or open a circuit. Circuit Diagram of the 555-Timer latch Circuit. In this circuit used 2 relays. After several months of house renovation I now have time to pursuit this hobby again. When we press push button, relay should be on, It means we use Normally Open type push button because when we press this switch supply goes forward. The switch, S1, triggers the SCR latch, so that current flows from the anode to cathode, turning on the buzzer. This is ON OFF switch circuit by using the single pushbutton switch. I have this latching circuit diagram which I would like to use to switch power on and off to the rest of the circuit (a 555 and a 4017be IC.) So a latch is used to store 1 bit of data. Mouser offers inventory, pricing, & datasheets for Switch ICs. Whereas the circuit used in the figure 2 requires a positive pulse to latch the output of the 555 IC, both the circuits can provide 200mA output current that can easily drive a relay switch and can also be used as an input to an electronic application. Once this switch is pressed down, the buzzer turns on. You can also use PC817 in place of MCT2E. When you give the supply to the connection, the output load is in OFF. Operating voltage of both the circuits are 5V to 12V DC. Latching Switch Circuit. The soft latch circuit is suitable for battery-operated portable instruments because it has a zero voltage in the off state. The LED along with the 330 resistor are the output of the circuit. Heres a simple latch-up circuit using 555 timer and opto-coupler MCT2E. Here relay is 24 V DC operated. MLX92242. The output of the voltage divider circuit is connected to pin 6 of the IC. This latch Make the connection as the given diagram. This is how the latch circuit operates. When 0.65V is fed into the base of the BC547 transistor, it turns on. The 330 resistor limits current to the LED so it doesn't blow. Step 2:-When supply comes to relay coil, relay should be ON. It is a circuit which stores data in digital form that is a logic 1 or logic 0. The latch is a word which used in digital electronics. The schematic of the 555-timer based on-off switch is given below. These two step we see in following picture:-Relay Latching Circuit using Push Button This programmable advanced Hall-effect switch/latch IC enables end-of-line (EOL) calibration to reduce mechanical tolerances assuring reliable and