Free Circuit Diagram

You can use this circuit to give auto trigger for your secondary flash light. You don’t have to worry about wiring for the control, because using this circuit your secondary flash will be automati8cally triggered when it receive the light signal from the primary flash. Look at the circuit’s schematic diagram below. The [...]

Using a standard fluorescent tube lamp (TL), you can make your own disco light, similar to a stroboscope light. You can even use a half-broken lamp, which one side of the heating filaments has broken. This circuit use only one side heating filament inside the tube. Look at the circuit’s schematic below. [...]

Testing whether a transistor is shorted or open usually done by ohm meter. You test if the base to emitter  or collector permit a current flow in one direction. Here is the circuit’s schematic diagram: The 555 timer ( IC1 ) operate as a 12hz  oscillator. The output of this oscillator (pin 3) [...]

Pulse width modulator produce a PWM signal, a pulse with a constant frequency but with the duty cycle vary according to a modulating signal. Here is the schematic diagram of pulse width modulator circuit using 555 IC as the active component: This pulse width modulator circuit need external pulse train input to trigger [...]

Sawtooth wave oscillator  circuit can be implemented using several methods, here we present one design that employs 555 IC.  Here is the schematic diagram of the circuit: The core of the circuit uses  general 555 oscillator configuration, but instead of using a fixed resistor to limit the current for charging the capacitor, we [...]

This audio frequency meter uses 555 IC as a monostable multivibrator (one-shoot trigger). A monostable multivibrator can act as a frequency-to-voltage converter because it produce a fixed pulse width, with the repetition rate/density is proportional to the triggering input frequency. Here is the circuit’s schematic diagram: For resistor R1, because it set the [...]