Checker Circuits
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The input consists of two comparators that operate with different reference voltages supplied by separate potential dividers. .. -
This circuit outputs a TTL-compatible - pulse whenever the signal falls within the limits set by potentiometers .. -
This window generator uses a single LM324 op amp and features two adjustable set points. When the two comparators formed b.. -
In Fig. 104-3(a), when Vin is between reference voltages Vi and Vu, output Vout goes low. If Vin> Vl, IC2 produces a low.. -
The high switching speed, low offset current and low offset voltage of the HA-4900 series make this window detector extreme.. -
The battery tester uses four transistors and two LEDs to indicate the condition of any battery you want to test. Q3 and Q4 are connected in a Darlington configuration that has extremely high gain. LED L2 lights when a small positive potential appears on the.... -
This circuit uses a pair of Zener diodes to monitor battery voltage of a 12-V battery. If below 11 V, 1)1 ceases to conduct, pin 3 of 102 goes high, setting FF IC2 turning on Ql, Kl, and the battery charger... -
Using this circuit, tiiree levels of voltage can be displayednormal (11 to 15 V), liigh (>15 V), and low (11 V). When the voltage is low, the LED glows steadily. In the normal range, the LED is off. When the voltage is high, the LED blinks at a 1-Hz rate. .. -
The LM3914A bargraph LEDis used here as a voltmeter for battery testing. The circuit is powered by a 4.5-V battery and compares the battery under test with an internally derived reference, set by R1/R2/P1. Each LED of the 10 represent 10% of full scale... -
This circuit consists of a tri-color LED, a resistor, wire, and a coin-size test plate. You will have to build two such circuits one for each black clamp on a set of auto battery jumper cables. The author installed the circuits inside the black clamps.... -
With SI open, base bias is supplied to Q2 through a voltage divider (formed by R2 and R3), thus turning on the green element in the LED. That indicates that power is being supplied to the project. If you close SI, current through R1 biases Ql on, thereby.... -
By judging the rate at which a particular LED flashes, you`ll be able to estimate the resistance. The circuit consists of two IC`s (1 4011 CMOS quad 2-input, NAND gate, Ul; and a 4024 binary counter, U2), seven LEDs, and a handful of additional .components..... -
This decade box can be set for any resistance value between 10 and 11.1 in 10- stops. A switch can be used to configure several RC configurations. Use close tolerance components in the circuit. If possible, check components with-an accurate bridge or.... -
At the heart of the cable tester are two op amps, which are used as a window- comparator to indicate a short- or open-circuit condition. A third op-amp comparator is used to indicate a good circuit (i.e., neither open nor shorted). Colored LEDs are used to.... -
The circuit is built around a 741 general-purpose op amp that is configured as a voltage follower; with the components shown, the op amp has a voltage gain of one. The output of the 741 is used to drive a 50- meter movement. Potentiometer R7 is used to zero.... -
The tester provides an audible indication of the logic level of the signal presented to its input. A logic high is indicated by a high tone, a logic low is indicated by a low tone, and oscillation is indicated by an alternating tone. The input is high.... -
This electronic pressure gauge uses a Wheatstone bridge-type pressure sensor tb drive a 3 A digit A/D converter and a display. IC1 is a pump (quad) that interfaces the bridge sensor to the A/D converter. R16 provides zero adjustment and R6 provides.... -
Transistors Ql and Q2, together with resistors Rl through R7, make up the input balancing stage, which senses the resistance between points X and Y. The input stage is essentially a bridge, consisting of Rl, R2, R6, R7, and the resistance between points X.... -
The tester consists of a rectifier circuit and a multivibrator circuit. The ac voltage is half-wave rectified by diode D1 and stored in capacitor CI. Resistor Rl is used to limit the current through D1 to a safe value. The voltage stored across CI supplies.... -
The circuit uses Ql to buffer the right-channel balance output while Q2 and Q3 form a VOX circuit. When the signal level from the microphone goes high, the output of the VOX also goes high and the multiplexer inside IC1 switches the high-gain left-channel.... -
Transmitter operation. Operating power for the transmitter circuit is derived directly from the ac line. The dc power to operate the circuit is generated in two stages, one for an RF power-am-plifier stage, and the second for the remainder of the circuit..... -
Driving a D/A converter with an A/D converter provides an overall analog-hold function, which though limited in output resolution, offers zero voltage droop and infinite hold time. The A/D converter shown (IC1) includes a 12-bit compatible track/hold at its.... -
To display an rf signal, connect LI to the transmitter and points A and B to the vertical plates of the oscilloscope. Adjust LI for minimum SWR and C3 for the desired trace height on the CRT.. -
Though this setup can act as a cost-effective current source with an output accurate to 1%, the voltage offset will turn on the current source even when Vqq equals Vin. 2. Modifying the configuration of Figure 1 can rectify the problem of the current source.... -
The dc values of op-amp offsets can`t always be taken for granted when delivering ac outputs. No device is ever exactly symmetrical for maximum positive slew rate versus maximum negative slew rate. Consequently, there is always some range of output slew.... -
Liquid crystal displays are currently available in several versions and various sizes. The wide variety of features, has resulted in there a little chaos in the provision of the pin. So that even when, after much effort, we can find a screen that fits our.... -
This circuit shows how to cascade counters and retain correct leading zero blanking. The NAND gate detects whether a digit is active since one of the two segments a or b is active on any unblanked number. The flip flop is clocked by the least significant.... -
The circuit provides a simple means of determining the succession of phases of a 3-phase 120 V source used in synchro work. Terminals A, BT and C are connected to the three terminals of the source to be checked. If the neon bulb lights, interchange any two.... -
The circuit uses a CA3130 BiMOS op amp as the sample-readout amplifier for the storage (sample-holding) capacitor Cl, and a CA3080A as the sample-control amplifier. .. -
This circuit rapidly charges capacitor CST0 to a voltage equal to an input signal. The input signal is then electrically disconnected from the capacitor with the charge still remaining on CSTO. Since CST0 is in the negative feedback loop of the operational.... -
When switch SWl is positive, the FET is turned on, and has a resistance of about 400 ohm. The input voltage charges up the capacitor through the FET. When SWl is negative, the FET is turned off (pinched off). To get a long storage time, the op amp must have.... -
During normal' 'hold'' mode, the replicated analog voltage is buffered straight through the S/H amplifier to the output. Upon issuance of a SAMPLE signal, the S/H amplifier is placed in the hold mode, holding the voltage until the new analog voltage is....
New Circuits
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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.....
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