Simple Analog Comparator Circuit using lm311

This is one of the common circuit blocks being used both in digital and analog electronics. Its output is dependent on the relationship of its two input pins. One of the inputs is set to give the reference voltage while the other one is commonly connected to different sensors. If the reference voltage was overcome by the input connected to the sensor, the output of the comparator changes.

In this circuit, the we'll use an LDR.

 

The advantage of a comparator IC than an opamp used as an comparator is the property of IC comparators to be open collector output. Having this feature, we can set the output of the comparator beyond its biased voltage.

Latching Relay Circuit

There are situations that we need to implement latching relay action. This can be implemented by connecting the relay pins to proper configuration with respect to the button and the power source. In this blog post, I will present the circuit/schematic and demo video simulation of a latching relay.

Here is the schematic:

The components in this circuit are:

1. 1 latching switch --> serves as the reset

2. 1 normally open switch --> acts as the trigger button

3. 1 diode(1n4001) --> snubber diode against kick voltage

4. 1 spdt 5v relay

5. 1 LED --> serves as the load

6. 1 330 ohm resistor --> current limiting

**The power source is operating in 5volts.

The circuit can also be triggered by logic ICs(TTL/CMOS) using proper interfacing method. I usually use another relay that serve as the trigger button when interfacing ICs to latching relay circuit.

Here is the demo video:

Simple Light or Dark Activated Switch Circuit

This is a basic circuit that can be constructed by students.

It uses a transistor as a switch, LDR as the sensor, variable resistor for calibration, diode as a snubber and the relay as the switching component.

Simple utility amplifier (using LM386)

Simple amplifiers are easy to build. Specially if you're using amplifier ICs.

Here is my simple utility amplifier. I used this on project development, etc.

This is not an advisable design but enough if you just want to hear louder sound from you coming input.

Here is the schematic.