Free Circuit Diagram

A square wave oscillator using 555 IC can be configured to give symmetric oscillation (50% duty cycle). Other circuit uses diodes to split the charging and the discharging paths through different resistors, but here we need no such diodes. Here is the schematic diagram: The time period for the output high is the [...]

LM56 is a monolithic  thermostat designed for simple temperature control. The chip has two programmable threshold that can be used to drive a fan and or alarm.  Here is the schematic diagram of the fan control circuit: /caption] The circuit will turn on the fan when the temperature rise above 50 [...]

This is pressure sensor signal conditioning circuit. It is simple and inexpensive circuit because it has small geometry and simple pressure sensor. It just uses a single Operational Amplifier. This circuit obtain power from from 3-V battery. To work properly this circuit must work in  0 C to 50 C temperature range. Here is the [...]

You might think that hum noise is produced by electronic device with improper design, yes you’re right. And you might choose to solve the trouble maker, the source. You begin to check the grounding, the cabling, casing, and many more things you can do to eliminate the hum heard from your amplifier. You might [...]

In application that demand for high current, Nicad (NiCd) rechargeable battery still has the unbeatable performance compared to NiMH and Lithium battery. The charger circuit here is smart in the way it handle the wrong polarity of the battery placement. The core of this battery charger circuit is the Q2, configured a constant [...]

UHF antenna booster can be used for better reception, especially when you’re far from TV station / relay transmitter. This UHF antenna booster works in 400-850 MHz range. Here is the circuit diagram of the UHF antenna booster: The circuit use only one transistor, but it gives you 10 to 15 dB amplification, [...]