Archive for category: Tester Circuits

SWR Meter For QRP (1 WATT) Level

Tester Circuits | By: Diagram mania

This circuit diagram shows us about simple SWR which is built using readily available parts. Take a note that to ensure accurate power reading, no attempt has been made . If we want a circuit that would fit in a small enclosure, and give an indication of minimum SWR, this circuit does the trick. The […]

Cable Reflection Tester

Tester Circuits | By: Diagram mania

This is a Cable Reflection Tester circuit. This circuit can be used to check coax cable runs for shorts or even impedance mismatches. This circuit will send a pulse down the circuit, then the return signal can be checked on an oscilloscope. The distance can be determined by using this equation:distance = time x speed […]

Simple Discrete Logic Probe

Tester Circuits | By: Diagram mania

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 the schematic diagram of the circuit: When the probe is not touching any circuitry, this circuit consumes no current. It can happen because the […]

Simple Signal Injector

Tester Circuits | By: Diagram mania

This is a signal injector circuit.  Signal injector is important tool for troubleshooting your electronic circuits. As an example, this circuit can be used to test amplifier circuit.  Here is the schematic diagram of the circuit: This circuit also a lot of harmonics. By connecting the ground clip to the 0v rail and move through […]

Wheatston Bridge PWM Signal Conditioner

Tester Circuits | By: Diagram mania

This is a schematic diagram of a Wheatston Bridge PWM Signal Conditioner circuit. This circuit uses the MAX1452 signal conditioner. A ratiometric compensated output for the Wheatstone Bridge is generated by the MAX1452. Then the output of the Wheatston bridge is converted to a PWM output. the PWM-output duty cycle changes accordingly, as the MAX1452 […]

OP90 4 mA to 20 mA Current Loop Transmitter

Tester Circuits | By: Diagram mania

An output of 4 mA to 20 mA that is linearly proportional to the input voltage is provided by the current transmitter on figure below. Line rejection is 0.0005%/volt and linearity of the transmitter exceeds 0.004%. Here is the schematic diagram of this current loop circuit: The REF-02EZ provides biasing for the current transmitter. The […]

Differential Current Sensing Inside H Bridge

Tester Circuits | By: Diagram mania

A differential current sensing that is inserted inside a H bridge circuit. is shown in the schematic diagram below. This circuit is one example of AD8205 application. The AD8205 measures current in both directions as the motor changes direction and H-bridge switches. This circuit has high accuracy in current measurement because AD8205 is placed in […]

Multilevel Continuity Tester

Tester Circuits | By: Diagram mania

This continuity tester not only show if a connection is continue or not, but also determine the range  of  its conductivity level. Here is the schematic diagram of the circuit: Finding wiring trouble is easier if we know the quality of the connection, and this continuity tester give rough estimation. Small transistors will be sufficient […]

Simple Transistor Tester Using 555 IC

Tester Circuits | By: Diagram mania

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) drives the […]

Varactor Test (Experiment) Circuit

Tester Circuits | By: Diagram mania

A varactor is also known as a varicap or a variable capacitance diode. An electrically controllable capacitance is provided by this varactor which can be used in tuned circuits. What makes it’s advantageous in many application are the small size and inexpensive. If compared to a manually controlled variable capacitor, this varactor has disadvantages such […]