Mutchus

This FM transmitter circuit can be used as a wireless microphone,  can be received by an ordinary 88- to 108-MHz FM broadcast receiver. For the power supply, this transmitter circuit is powered by a 9 V battery. To comply with the radiation limit of FCC rules, keep the antenna length under 12 inches. L1 is 6 turns of #24 wire wound around a pencil or a 1/4″ form, with turns spacing of 1 wire diameter. C6 is a gimmick capacitor which has value about 1 pF..  9V Wireless Microphone FM Transmitter Circuit Diagram

4.2.1.1 Defects of a simple Electric Cell The practical value and performance of simple cells is limited by the following defects: (a)          Polarization In the reaction in the simple cell, hydrogen gas is evolved. It collects in bubbles around the positive electrode and-eventually insulate the positive electrode from the solution.  This  stops  the reaction. This process is known as polarization. It is minimized by use of a depolarizer.  This is a chemical which reacts with the hydrogen to produce water e.g. manganese dioxide. (b)          Local Action Impurities such as iron and lead embedded in the zinc  electrode  form small local cells. The impurity acts as the positive electrode and zinc as the negative. The formation of these local cells between the impurities and the zinc electrode is referred to as local action. It tends to wear the zinc electrod...

How to Build a Bipolar Power supply for Battery instruments . A bipolar power supply overcomes those limitations. Most importantly, it can provide both positive and negative voltages from a single pair of terminals. There are no relays to switch polarity, so a bipolar supply can move smoothly from positive, through zero, to negative voltages.   Bipolar Power supply for Battery instruments Circuit Diagram It also regulates zero volts or other very small voltages. In this Bipolar Power supply for Battery instruments circuit diagram to generate regulated ± 5-V supplies from a pair of dry batteries, the circuit of Fig. 1 is commonly used. In order to give protection from inadvertent reverse connection of a battery, a diode in series with each battery would produce an unacceptable voltage drop.  The more effective approach is to fit diodes Dl and D2 as shown in Fig. 2, in parallel with each battery. When the supply is switched off, there is the risk of a reverse bias being ...

An LED is usually a series resistor needed to ensure that the LED does not get too much power. The disadvantage of such a resistor is that the current thus also changes by the LED and the brightness as the voltage changes.  This circuit prevents that, by independent of the voltage, a constant current through the LED.The circuit uses two transistors and two resistors. The circuit can be connected to voltages of from 5 to 24 V.   Constant LED Power Supply Circuit Diagram

Here is a simple electronic projects of relay toggle circuit with 555 timer .  This 555 timer circuit below toggles a relay when a button is pressed. Pins 2 and 6, the threshold and trigger inputs, are held at 1/2 the supply voltage by the two 10K resistors. When the output is high, the capacitor charges through the 100K resistor, and discharges when the output is low. When the button is pressed, the capacitor voltage is applied to pins 2 and 6 which causes the output to change to the opposite state. Relay Toggle Circuit Diagram: When the button is released, the capacitor will charge or discharge to the new level at the output (pin 3). The parts are not critical, the resistors can be somewhat higher or lower, but the 2 resistors at pins 2 and 6 should be equal values, and the resistor connected to the cap should be 10 times greater or more. Advantages of this circuit are the large hystersis range at the input which avoids false triggering, and only a few parts are needed for cons...

We recently bought a train set made by a renowned company and just couldn’t resist looking inside the locomotive. Although it did have an electronic decoder, the DCM motor was already available 35 (!) years ago. It is most likely that this motor is used due to financial constraints, because Märklin (as you probably guessed) also has a modern 5-pole motor as part of its range. Incidentally, they have recently introduced a brushless model.  The DCM motor used in our locomotive is still an old-fashioned 3-pole series motor with an electromagnet to provide motive power. The new 5-pole motor has a permanent magnet. We therefore wondered if we couldn’t improve the driving characteristics if we powered the field winding separately, using a bridge rectifier and a 27 Ω current limiting resistor. This would effectively create a permanent magnet. The result was that the driving characteristics improved at lower speeds, but the initial acceleration remained the same. But a constant 0.5 A flows...

  This cell phone jammer operates at GSM800 frequency since most mobile phones use it to operate. So the selected VCO is a sweeping oscillator, which is very effective but may be hard to construct for the beginners without nice RF-testing equipment. As a noise source you can use 45MHz clock oscillator which is driving Local Oscillator port located on a mini-circuit mixer. There is also an impedance matching network for Local Oscillator signal to pass through it. It is used to equate impedances of the clock oscillator and the port of the mixer. RF input (which is this port of the mixer) connected to the first 800MHz cell phone antenna, and the RF output is sent to the mini-circuit amplifier. This amplifier increases the output power for 15-16dbm. The amplified signal then sent to the second cell phone antenna.  works All cell phones which use GSM800 have their transmitted and received frequencies always separated by 45MHz. So when the mobile phone tries to call it is blocked b...

A sound generator is a vibrating object which produces a sound. How to Build a Simple Run-Down Clock Circuit Diagram ? This is a simple sound generator circuit diagram this is a simple and easy to use. Enter your desired frequency and press play. In this circuit used in electronic roulette or dice games, this circuit produces a clock signal that initially is several tens of kHz (depending on C2) and gradually decreases to zero in about 15 seconds, as CI discharges through R4.  Simple Run-Down Clock Circuit Diagram