Archive for tag: 555

Beam-break Detector For Camera Shutter or Flash Control

Control circuits | By: Diagram mania

This circuit is presented as an alternative to the IR beam break detector featured in the June 2009 issue (Silicon Chip). In order to make it relatively insensitive to ambient light, it uses a standard IR receiver IC such as the Jaycar ZD-1942. This has a high output (+5V) as long as a modulated beam […]

Precision Inductance and Capacitance Meter

Measurement Circuits | By: Diagram mania

This circuit for measurement of inductance and capacitance can be used to test whether the values of inductors and capacitors quoted by the manufacturer are correct. The principle used in the circuit is based on the transient voltages produced across inductors and capacitors connected as series R-L and R-C networks, respectively, across a constant voltage […]

High Low Voltage Cutout Without Timer

Timer Circuits | By: Diagram mania

This inexpensive circuit can be connected to an air-conditioner/fridge or to any other sophisticated electrical appliance for its protection. Generally, costly voltage stabilizers are used with such appliances for maintaining constant AC voltage. However, due to fluctuations in AC mains supply, a regular ‘click’ sound in the relays is heard. The frequent energisation/de-energisation of the […]

USB-Powered PIC Programmer

Uncategorized | By: Diagram mania

This simple circuit can be used to program the PIC16F84 and similar “flash memory” type parts. It uses a cheap 555 timer IC to generate the programming voltage from a +5V rail, allowing the circuit to be powered from a computer’s USB port. The 555 timer (IC1) is configured as a free-running oscillator, with a […]

12V Powered 12V Lead Acid Battery Charger with Indicator

Battery and Charger Diagram | By: Diagram mania

Some of you might wonder why a charger is needed at all, to charge a 12 Volt battery from a 12 Volt source! Well, firstly the “12 Volt” source will typically vary anywhere from 11 Volt to 15 Volt, and then a battery needs a controlled charge current and voltage, which cannot result from connecting […]

Police Lights an LED Project

Lighting Circuits Diagram | By: Diagram mania

This circuit uses a 555 timer which is setup to both run in an astable operating mode. This generates a continuous output via Pin 3 in the form of a square wave. When the timer’s output changes to a high state this triggers the a cycle on the 4017 4017 decade counter telling it to […]

Model Theatre Lighting Dimmer

Lighting Circuits Diagram | By: Diagram mania

This circuit is the basis for the dimmers in a model theatre lighting system which uses touch globes as the light source. The circuit is based around a 555 timer, driving a Triac. All dimmers share the one power supply and zero-crossing detector. As it will only work if there is a common AC/DC return […]

Toy Organ

Uncategorized | By: Diagram mania

This circuit produces a tone according to the button being pressed. Only 1 button can be pressed at a time, that’s why it is called a monophonic organ. You can change the 1k resistors to produce a more-accurate scale. Circuit diagram Parts: R1-4 1k Resistor R5 4.7k Resistor P1 10k Trimpot (Potentiometer) S1-5 Switch C1 […]

Ultra Low Power LCD

Uncategorized | By: Diagram mania

This circuit serves as an ultra-low power replacement for multiple LED on-off indicators. It also has the advantage of being easy to read in full daylight. With the parts shown, it is possible to display four bits of information.The display that I used has three digits and 2 decimal points for a total of 23 […]

LED Scanner

Lighting Circuits Diagram | By: Diagram mania

Here is a simple LED chaser simulating a scanner through the back and forth light effect. It used high bright White LEDs to give the chaser effect. The circuit uses an oscillator to produce fast pulses and a decade counter to drive the LEDs. IC1 is designed as an astable multivibrator to give continuous positive […]