Need help Gary metal detector

[yhl]

I did a circuit. But not enough depth of detection / 2.5 cm coin is only 10 cm.
Circuit the total current only 55 mA. Are there problems?
Test point voltage is normal

[oros27]

TA5.rar

[oros27]

Approximately 12 inch OD and wound with a 20 1/2 AWG.
Approximately 26 Turns
Inductance, Approximately 400 uhy measured at 1 Khz.
DC Resistance aprox 0.8 ohms.

[yhl]

Thank you

There may be / I is a 0.51CM line. Diameter 20CM, 30 laps of the BFO coil

[yhl]

Gary detector test coin ten inches. Is buzzer instructions? Or meter instructions?

Gary detector test coin ten inches. Is buzzer instructions? Or meter instructions?

[WM6]

Gary detector test coin ten inches. Is buzzer instructions? Or meter instructions?

Depth not depend so much of used instrument, but meter can be more sensitive on tiny targets.

[yhl]

What value of R5 is the best? R5 can increase the total current change it?

What value of R5 is the best? R5 can increase the total current change it?

[WM6]

What value of R5 is the best? R5 can increase the total current change it?

From which schematic?

If R5 is coil damping R, then you have to chose it regarding your coil. You chose it so, that fall of backfly impulse to bottom is as short as possible and at the sametime as stright as possible. You need scope and to find best value of R try first find it with pot.

[yhl]

HELP

Friends want to know Gary Detector IC555. What is the model used. Is the NE555 or ICM7555

[yhl]

TL081 AD811 can be used instead?

TL081 AD811 can be used instead????//??/

[yhl]

HELP

Total current is too small 55MA

[yhl]

Gary IC5 IC6 IC7 IC8 what model? Such as the NE555 or ICM7555.

Gary IC5 IC6 IC7 IC8 what model? Such as the NE555 or ICM7555.
Which is best?

[Qiaozhi]

Total current is too small 55MA

Which schematic are you using?

[yhl]

is

Gary Pulse 1

[Qiaozhi]

Gary Pulse 1

Have you tried adjusting the pulse width preset (R5A)? This should affect the current drawn by the circuit.