CMOS Flip Flop Toggle Relay Circuit Diagram 4013

Description

The schematic below employs a CMOS dual D flip-flop (CD4013) to switch a relay or other load with a push button. Multiple buttons can be connected in parallel to activate the relay from several positions.

A high signal from the button is coupled to the set input through a small (0.1uF) capacitor. The high signal from the Q output is inverted by the top transistor, providing a low reset level to the reset input for approximately 400 mS, after which the reset input returns to a high state and resets the flip-flop. The bottom flip-flop section is configured for toggling operation, changing state on the rising edge of the clock input or concurrently with the upper flip-flop reaching the set condition. The switch is mitigated against bounce due to the brief duration of the set signal compared to the extended time before the circuit is reset. The Q or Qbar outputs can only deliver around 2 mA of current, necessitating a buffer transistor or power MOSFET to drive a relay coil, lamp, or other load. A 2N3904 or any small signal NPN transistor is suitable for relay coil resistances of 250 ohms or greater. A 2N3053, a medium-power (500 mA) transistor, should be used for coil resistances beneath 250 ohms. The 47-ohm resistor and 10uF capacitor are used to isolate the circuit from the power supply and filter out any transient, short-lived electrical disturbances that might be present. The RC network (.1/47K) at the SET line (pin 8) functions as a power-on reset, ensuring the relay is de-energized when power is initially applied to the circuit. The reset concept was proposed by Terry Pinnell, who utilized the circuit to control a shed light from multiple locations.

More about components

The core of this circuit is the CD4013, a common CMOS dual D flip-flop. This integrated circuit is a versatile component used for storing and switching digital signals. The CD4013 contains two independent flip-flops, each with inputs for clock, data, set, reset, and enable signals. These flip-flops can be used to create sequential circuits, memory, and timing circuits. The IC operates using complementary metal-oxide-semiconductor (CMOS) technology, which minimizes power consumption and ensures reliable operation over a wide voltage range. The key features of the CD4013 include its low power consumption, high noise immunity, and availability in both single and dual-in-package (DIP) versions. It's widely used in various applications, including digital logic design, instrumentation, and control systems. Its availability and relatively low cost further contribute to its popularity. This IC has a total of 14 pins, providing flexible connectivity for different circuit configurations. The pinout is specifically designed for easy integration into a variety of electronic designs. The CD4013 is a reliable and cost-effective solution for many digital circuit applications. The IC's performance is characterized by its fast switching speeds and low propagation delays, making it suitable for high-speed digital systems. The robustness of the CMOS technology ensures long-term reliability and stability. This IC can be operated over a wide temperature range, further enhancing its reliability in various environments. The CD4013 is available in several package options, including the standard DIP (Dual Inline Package) which is commonly used for prototyping and small-scale projects. The IC's small size makes it ideal for space-constrained applications. The CD4013 is a dependable and readily accessible component for a wide range of digital circuit designs.

Circuit diagram