Archive for category: Digital Circuit

Photo Timer Circuit Circuit

Digital Circuit | By: Diagram mania

Circuit diagram Time is set by potentiometer R2 which provides a range or 1 sec. To 100 seconds with timing capacitor C1 of 100uF. The output at pin 3 is normally low and the relay is held off. A momentary push on switch S1 energies the relay which is held closed for a time 1.1 […]

Time Delay Relay Circuit

Digital Circuit | By: Diagram mania

A time delay relay is a relay that stays on for a certain amount of time once activated. This time delay relay is made up of a simple adjustable timer circuit which controls the actual relay. The time is adjustable from 0 to about 20 seconds with the parts specified. The current capacity of the […]

24 Hour Timer Circuit

Digital Circuit | By: Diagram mania

Description: These two circuits are multi-range timers offering periods of up to 24 hours and beyond. Both are essentially the same. The main difference is that when the time runs out, Version 1 energizes the relay and Version 2 de-energizes it. The first uses less power while the timer is running; and the second uses […]

Asymmetric Timer Circuit

Digital Circuit | By: Diagram mania

Description: A timer circuit with independent mark and space periods. Circuit diagram Notes: A simple astable timer made with the 555, the mark (on) and space (off) values may be set independently. The timing chain consists of resistors Ra, Rb and capacitor Ct. The capacitor, Ct charges via Ra which is in series with the […]

5 to 30 Minute Timer Circuit

Digital Circuit | By: Diagram mania

Descriptipn: A switched timer for intervals of 5 to 30 minutes incremented in 5 minute steps. Circuit diagram Notes: Simple to build, simple to make, nothing too complicated here. However you must use the CMOS type 555 timer designated the 7555, a normal 555 timer will not work here due to the resistor values. Also […]

Periodic Timer Circuit

Digital Circuit | By: Diagram mania

Description: A switched timer with equal make and equal space periods timing adjustable from over 6 minutes to 38 minutes. Circuit diagram Notes: This timer circuit is similar to the 5 to 30 minute timer except that when switch S1 is closed, the on/off action of the circuit will continue indefinately until S1 is opened […]

Time Delay Relay II Circuit

Digital Circuit | By: Diagram mania

When activated by pressing a button, this time delay relay will activate a load after a specified amount of time. This time is adjustable to whatever you want simply by changing the value of a resistor and/or capacitor. The current capacity of the circuit is only limited by what kind of relay you decide to […]

Timed Beeper Circuit

Digital Circuit | By: Diagram mania

Beeps 7.5 seconds after a preset time Adjustable time settings: 15 sec. 30 sec. 1 min. 2 min. & others Circuit diagram Parts: R1 220R 1/4W Resistor R2 10M 1/4W Resistor R3 1M 1/4W Resistor R4 10K 1/4W Resistor R5 47K 1/4W Resistor C1 100nF 63V Polyester Capacitor C2 22µF 25V Electrolytic Capacitor D1 1N4148 […]

Tan Timer Circuit

Digital Circuit | By: Diagram mania

Six timing positions suited to different skin types Timing affected by sunlight intensity Circuit diagram Parts: R1 47K 1/4W Resistor R2 1M 1/4W Resistor R3,R5 120K 1/4W Resistors R4 Photo resistor (any type) C1,C3 10µF 25V Electrolytic Capacitors C2 220nF 63V Polyester Capacitor D1,D2 1N4148 75V 150mA Diodes IC1 4060 14 stage ripple counter and […]

Repeating Interval Timer Circuit

Digital Circuit | By: Diagram mania

Do not use the “on-board” relay to switch mains voltage. The board’s layout does not offer sufficient isolation between the relay contacts and the low-voltage components. If you want to switch mains voltage – mount a suitably rated relay somewhere safe – Away From The Board. I’ve used a SPCO/SPDT relay – but you can […]