Temperature gauge circuit using LM324 IC (PCB)

Temperature gauge circuit using LM324 IC (PCB)

Temperature gauge circuit using the LM324 IC

The temperature level is displayed using 4 LEDs:
A green LED indicates that the temperature is OK.
Two yellow LEDs indicate that the temperature is higher than normal.
A red LED indicates that the temperature is very high

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Car battery monitor circuit using 4 LEDs

Car battery monitor circuit using 4 LEDs

Car battery monitor circuit using 4 LEDs

This simple Car battery monitor, allow us to know the voltage of the battery at all times. To achieve this 4 leds are placed somewhere on the dash of the car. Each LED has a label indicating the battery voltage at that time.

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8 LED VU meter circuit using LM324 IC

8 LED VU meter circuit using LM324 IC

8 LED VU meter made of IC-LM324.

This circuit can be used to display the variation of an audio signal in a group of 8 LEDs, behaving like a VU meter. We could use an specific integrated circuit used for VU meters, but we decided to use a readily available integrated circuit: The LM324 op amp.

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Electric Current Flow Indicator

Electric Current Flow Indicator

This Electric Current Flow Indicator gives a visual indication that there is a current flow. Possible applications for this small circuit may be: a battery charger, a voltage power source, etc.

In order to achieve our objective we place 3 rectifier diodes in series, which in turn are in series with the load / battery.

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High - Low Temperature Indicator using LM35, 741 and LEDs

High – Low Temperature Indicator using LM35, 741 and LEDs

This High – Low Temperature Indicator shows us, by means of two LEDs, when the sensed temperature is above or below a set limit.

When the temperature is above the pre-set temperature level, LED D1 will light up and if it is below, LED D2 will light up.

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Automatic night light circuit with one LED

Automatic night light circuit with one LED

Automatic night light circuit with one LED

This Automatic night light circuit is simple, interesting and easy to do. Surely you have seen the new lanterns made of the new high-capacity LEDs. The idea is to get something that looks like.

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ON-OFF Switch circuit using a 555 timer (PCB)

ON-OFF Switch circuit using a 555 timer (PCB)

This ON-OFF Switch circuit using a 555 timer is simple, useful and easy to implement.

This circuit has many applications on places where it is necessary to activate and deactivate (connect and disconnect) an electrical or electronic device.

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Twilight switch circuit with operational amplifier and LDR

Twilight switch circuit with operational amplifier and LDR

This Twilight switch circuit activates a light, a lamp, a motor, etc., at the time of sunset and performs the reverse process at dawn.

This is an ideal circuit for activating a security light that must be on all night.

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