This is a very simple 5 watt CW TX based upon a TTL logic chip. There is just one "tricky" component and this is Cx. This component should have an impedance of about 10 - 50 ohms at the frequency of interest. If you wish to reduce the transmitter power,....
Probably the easiest way of doing automatic switch off is with relay logic. In the diagram, the box marked RL1 is the coil, the 2 in the coil box tells you there are two sets of contacts somewhere on the circuit, operated by this coil. In this simple....
Just to prove that transistors can also be useful in logic situations; this is a data latch and indicator which also is a data switch and has a bidirectional input/output port which can be read or switched. If the second transistor is off, a small currrent....
Despite exhaustive searching, every reasonably priced solenoid valve for controlling propane during pushbutton start required 12VDC, beyond the capabilities of a normal pump battery. I know that there are methods to generate HV pulses which will actuate the....
The schematic below illustrates 4 methods of controlling a relay with a digital logic signal. Figure (A) can probably be used in most cases where the relay coil requires 100 mA or less and the input current is 2 milliamps or more. The resistor value (R) is....
You're simulating a circuit, it requires several digital gates, but you don't have a mixed-mode simulator. What to do? One solution involves creating simplified versions of the logic functions. To do this, we look to the NMOS transistor implementation of....
It is a 32 Channel, 40Mhz, fully PCcontrolled TTL/CMOSlogic analyser with internal/external triggering and trigger delay. Internal triggering is fully maskable (High/Low/Don`t Care) on all 32 channels. The whole things fits on one single sided PCB with....
CMOS logic integrated circuits are extremely versatile devices which are used a great deal in modern electronic circuits. Like any logic circuits, those which employ CMOS devices can be difficult to test using an ordinary multi-meter as both static and....
Logic indicator circuit / logic probe is used to identify logic level at any point of logic circuitry. The indicator can be visual (using LED, LCD, of 7...
This schematic diagram shows a circuit of basic logic gate circuit. This PNP transistor circuit can act as OR gate or AND gate. If the input is closing of...
Interfacing high power load can be done in many ways, such as using voltage divider resistors, transformer, or optocoupler. In the circuit shown below, an optocoupler method is presented. This optocoupler serve the logic level translation with flexible....
Logic power control of analog regulator can be useful in application where a digital circuit/controller need to control power source, such as in EEPROM...
This is one of the simplest circuit for a PC parallel port based DLA. The Circuit is mainly used to protect the port which is fabricated on the motherboard itself..
We can use NE556 timer IC to make indication of static of terminal in digital logic audible.? Audible logic probe can be very useful when we have to visually...
This is a FM Transmitter circuit. This circuit uses logic gates. This transmitter circuit has a RF oscillator. This oscillator uses 10.7Mhz ceramic filter and...
This is a simple circuit of Logic Probe for Tri-state Logics. This circuit can be built only in a few hours. Besides that, this circuit has some other...
This is a Logic probe circuit is one, That is suitable for checking the voltage levels in the TTL circuit. It receives from the circuit being tested. Shows how high or low logic level one. The circuit when the input voltage to the probe Tip is higher than 2.....
Motorola SN54/74LS138 known to be 1-of-8 decoder or demultiplexer which is designed for high speed bar memory chip select address decoding. Below diagram illustrates logic diagram of this SN54/74LS138 demultiplexer. According to the SN54 datasheet, multiple....
This is simple logic probe circuit. Logic probe is used to determine if a point in a circuit has high or low state when the circuit is in operation.? Here is...
This logic probe can be selected to operate on TTL or CMOS logic levels, depending on switch S1. A string of resistors associated with switch S1 sets the threshold levels for a window comparator comprising IC1a and IC1b. Depending on whether the level....
NE556 timer can be used as an indicator of static of digital logic audible terminal. Audible logic probe is useful for inspecting a part visually while we also need to check the logic state on other point far from the part. NE556 acts as an oscillator....
Openbench Logic Sniffer is an open source logic analyzer. It`s designed to support the SUMP logic analyzer software at the lowest possible cost. Download the source and design files from the Gadget Factory project page. This project started in the comments....
A Dual Inline Package, or DIP switch can be used to select between 0 and 5 volts at some point in a circuit. Since the dip switch does not have any power or ground connectors this must be done externally. When the switch is turned on (in the "closed"....
When the input signal is logic 1, the display shows `H` and the loudspeaker emits a note which is an octave higher than the `low` tone. Operation of the circuit can be seen from the circuit diagram in figure 1 and the truth table in figure 2. When the input....
The Magnitude Comparator is a type of device which compares the two 4 bit binary inputs and determines the output which are the greater than, the equal, and the less than. This device states A>B, A=B, and A
Creating a 2-bit alu. It has 8 defined functions (the functions are defined by a 3bit code), AND XOR etc, and these functions act on two, 2-bit binary numbers and produce a 2-bit answer. From what I have done so far, I have a decoder that decodes what the....
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....